Getting Started with Vuex: A Beginner’s Guide

In single-page applications, the concept of state relates to any piece of data that can hange. An example of state could be the details of a logged-in user, or data fetched from an API.

Handling state in single-page apps can be a tricky process. As an application gets larger and more complex, you start to encounter situations where a given piece of state needs to be used in multiple components, or you find yourself passing state through components that don’t need it, just to get it to where it needs to be. This is also known as “prop drilling”, and can lead to some unwieldy code.

Vuex is the official state management solution for Vue. It works by having a central store for shared state, and providing methods to allow any component in your application to access that state. In essence, Vuex ensures your views remain consistent with your application data, regardless of which function triggers a change to your application data.

In this article, I’ll offer you a high-level overview of Vuex and demonstrate how to implement it into a simple app.

A Shopping Cart Example

Let’s consider a real-world example to demonstrate the problem that Vuex solves.

When you go to a shopping site, you’ll usually have a list of products. Each product has an Add to Cart button and sometimes an Items Remaining label indicating the current stock or the maximum number of items you can order for the specified product. Each time a product is purchased, the current stock of that product is reduced. When this happens, the Items Remaining label should update with the correct figure. When the product’s stock level reaches 0, the label should read Out of Stock. In addition, the Add to Cart button should be disabled or hidden to ensure customers can’t order products that are currently not in inventory.

Now ask yourself how you’d implement this logic. It may be trickier than you think. And let me throw in a curve ball. You’ll need another function for updating stock records when new stock comes in. When the depleted product’s stock is updated, both the Items Remaining label and the Add to Cart button should be updated instantly to reflect the new state of the stock.

Depending on your programming prowess, your solution may start to look a bit like spaghetti. Now, let’s imagine your boss tells you to develop an API that allows third-party sites to sell the products directly from the warehouse. The API needs to ensure that the main shopping website remains in sync with the products’ stock levels. At this point you feel like pulling your hair out and demanding why you weren’t told to implement this earlier. You feel like all your hard work has gone to waste, as you’ll need to completely rework your code to cope with this new requirement.

This is where a state management pattern library can save you from such headaches. It will help you organize the code that handles your front-end data in a way that makes adding new requirements a breeze.

Build a Counter Using Local State

In this section, we’re going to build a simple counter that keeps track of its state locally. Once we’re done, I’ll go over the fundamental concepts of Vuex, before looking at how to rewrite the counter app to use Vue’s official state management solution.

Getting Set Up

Let’s generate a new project using the CLI:

vue create vuex-counter

A wizard will open up to guide you through the project creation. Select Manually select features and ensure that you choose to install Vuex.

Next, change into the new directory and in the src/components folder, rename HelloWorld.vue to Counter.vue:

cd vuex-counter
mv src/components/HelloWorld.vue src/components/Counter.vue

Finally, open up src/App.vue and replace the existing code with the following:

<template>
  <div id="app">
    <h1>Vuex Counter</h1>
    <Counter/>
  </div>
</template>

<script>
import Counter from './components/Counter.vue'

export default {
  name: 'app',
  components: {
    Counter
  }
}
</script>

You can leave the styles as they are.

Creating the Counter

Let’s start off by initializing a count and outputting it to the page. We’ll also inform the user whether the count is currently even or odd. Open up src/components/Counter.vue and replace the code with the following:

<template>
  <div>
    <p>Clicked {{ count }} times! Count is {{ parity }}.</p>
  </div>
</template>

<script>
export default {
  name: 'Counter',
  data: function() {
    return {
      count: 0
    };
  },
  computed: {
    parity: function() {
      return this.count % 2 === 0 ? 'even' : 'odd';
    }
  }
}
</script>

As you can see, we have one state variable called count and a computed function called parity which returns the string even or odd depending on the whether count is an odd or even number.

To see what we’ve got so far, start the app from within the root folder by running npm run serve and navigate to http://localhost:8080.

Feel free to change the value of the counter to show that the correct output for both counter and parity is displayed. When you’re satisfied, make sure to reset it back to 0 before we proceed to the next step.

Incrementing and Decrementing

Right after the computed property in the <script> section of Counter.vue, add this code:

methods: {
  increment: function () {
    this.count++;
  },
  decrement: function () {
    this.count--;
  },
  incrementIfOdd: function () {
    if (this.parity === 'odd') {
      this.increment();
    }
  },
  incrementAsync: function () {
    setTimeout(() => {
      this.increment()
    }, 1000)
  }
}

The first two functions, increment and decrement, are hopefully self-explanatory. The incrementIfOdd function only executes if the value of count is an odd number, whereas incrementAsync is an asynchronous function that performs an increment after one second.

In order to access these new methods from the template, we’ll need to define some buttons. Insert the following after the template code which outputs the count and parity:

<button @click="increment" variant="success">Increment</button>
<button @click="decrement" variant="danger">Decrement</button>
<button @click="incrementIfOdd" variant="info">Increment if Odd</button>
<button @click="incrementAsync" variant="warning">Increment Async</button>

After you’ve saved, the browser should refresh automatically. Click all of the buttons to ensure everything is working as expected. This is what you should have ended up with:

The counter example is now complete. Let’s move and examine the fundamentals of Vuex, before looking at how we would rewrite the counter to implement them.

How Vuex Works

Before we go over the practical implementation, it’s best that we acquire a basic grasp of how Vuex code is organized. If you’re familiar with similar frameworks such as Redux, you shouldn’t find anything too surprising here. If you haven’t dealt with any Flux-based state management frameworks before, please pay close attention.

The Vuex Store

The store provides a centralized repository for shared state in Vue apps. This is what it looks like in its most basic form:

// src/store/index.js

import Vue from 'vue'
import Vuex from 'vuex'

Vue.use(Vuex)

export default new Vuex.Store({
  state: {
    // put variables and collections here
  },
  mutations: {
    // put sychronous functions for changing state e.g. add, edit, delete
  },
  actions: {
    // put asynchronous functions that can call one or more mutation functions
  }
})

After defining your store, you need to inject it into your Vue.js application like this:

// src/main.js
import store from './store'

new Vue({
  store,
  render: h => h(App)
}).$mount('#app')

This will make the injected store instance available to every component in our application as this.$store.

Working with State

Also referred to as the single state tree, this is simply an object that contains all front-end application data. Vuex, just like Redux, operates using a single store. Application data is organized in a tree-like structure. Its construction is quite simple. Here’s an example:

state: {
  products: [],
  count: 5,
  loggedInUser: {
    name: 'John',
    role: 'Admin'
  }
}

Here we have products that we’ve initialized with an empty array, and count, which is initialized with the value 5. We also have loggedInUser, which is a JavaScript object literal containing multiple fields. State properties can contain any valid datatype from Booleans, to arrays, to other objects.

There are multiple ways to display state in our views. We can reference the store directly in our templates using $store:

<template>
  <p>{{ $store.state.count }}</p>
</template>

Or we can return some store state from within a computed property:

<template>
  <p>{{ count }}</p>
</template>

<script>
export default {
  computed: {
    count() {
      return this.$store.state.count;
    }
  }
}
</script>

Since Vuex stores are reactive, whenever the value of $store.state.count changes, the view will change as well. All this happens behind the scenes, making your code look simple and cleaner.

The mapState Helper

Now, suppose you have multiple states you want to display in your views. Declaring a long list of computed properties can get verbose, so Vuex provides a mapState helper. This can be used to generate multiple computed properties easily. Here’s an example:

<template>
  <div>
    <p>Welcome, {{ loggedInUser.name }}.</p>
    <p>Count is {{ count }}.</p>
  </div>
</template>

<script>
import { mapState } from 'vuex';

export default {
  computed: mapState({
    count: state => state.count,
    loggedInUser: state => state.loggedInUser
  })
}
</script>

Here’s an even simpler alternative where we can pass an array of strings to the mapState helper function:

export default {
  computed: mapState([
    'count', 'loggedInUser'
  ])
}

This version of the code and the one above it do exactly the same thing. You should note that mapState returns an object. If you want to use it with other computed properties, you can use the spread operator. Here’s how:

computed: {
  ...mapState([
    'count', 'loggedInUser'
  ]),
  parity: function() {
    return this.count % 2  === 0 ? 'even' : 'odd'
  }
}

Getters

In a Vuex store, getters are the equivalent to Vue’s computed properties. They allow you to create derived state that can be shared between different components. Here’s a quick example:

getters: {
  depletedProducts: state => {
    return state.products.filter(product => product.stock <= 0)
  }
}

Results of getter handlers (when accessed as properties) are cached and can be called as many times as you wish. They’re also reactive to state changes. In other words, if the state it depends upon changes, the getter function is automatically executed and the new result is cached. Any component that has accessed a getter handler will get updated instantly. This is how you can access a getter handler from a component:

computed: {
  depletedProducts() {
    return this.$store.getters.depletedProducts;
  }
}

The mapGetters Helper

You can simplify the getters code by using the mapGetters helper:

import { mapGetters } from 'vuex'

export default {
  //..
  computed: {
    ...mapGetters([
      'depletedProducts',
      'anotherGetter'
    ])
  }
}

There’s an option for passing arguments to a getter handler by returning a function. This is useful if you want to perform a query within the getter:

getters: {
  getProductById: state => id => {
    return state.products.find(product => product.id === id);
  }
}

store.getters.getProductById(5)

Do note that each time a getter handler is accessed via a method, it will always run and the result won’t be cached.

Compare:

// property notation, result cached
store.getters.depletedProducts

// method notation, result not cached
store.getters.getProductById(5)

Changing State with Mutations

An important aspect of the Vuex architecture is that components never alter the state directly. Doing so can lead to odd bugs and inconsistencies in the app’s state.

Instead, the way to change state in a Vuex store is by committing a mutation. For those of you familiar with Redux, these are similar to reducers.

Here is an example of a mutation that increases a count variable stored in state:

export default new Vuex.Store({
  state:{
    count: 1
  },
  mutations: {
    increment(state) {
      state.count++
    }
  }
})

You can’t call a mutation handler directly. Instead, you trigger one by “committing a mutation” like this:

methods: {
  updateCount() {
    this.$store.commit('increment');
  }
}

You can also pass parameters to a mutation:

// store.js
mutations: {
  incrementBy(state, n) {
    state.count += n;
  }
}

// component
updateCount() {
  this.$store.commit('incrementBy', 25);
}

In the above example, we’re passing the mutation an integer by which it should increase the count. You can also pass an object as a parameter. This way, you can include multiple fields easily without overloading your mutation handler:

// store.js
mutations: {
  incrementBy(state, payload) {
    state.count += payload.amount;
  }
}

// component
updateCount() {
  this.$store.commit('incrementBy', { amount: 25 });
}

You can also perform an object-style commit that looks like this:

store.commit({
  type: 'incrementBy',
  amount: 25
})

The mutation handler will remain the same.

The mapMutations Helper

Similar to mapState and mapGetters, you can also use the mapMutations helper to reduce the boilerplate for your mutation handlers:

import { mapMutations } from  'vuex'

export default{
  methods: {
    ...mapMutations([
      'increment', // maps to this.increment()
      'incrementBy' // maps to this.incrementBy(amount)
    ])
  }
}

On a final note, mutation handlers must be synchronous. You can attempt to write an asynchronous mutation function, but you’ll come to find out later down the road that it causes unnecessary complications. Let’s move on to actions.

Actions

Actions are functions that don’t change the state themselves. Instead, they commit mutations after performing some logic (which is often asynchronous). Here’s a simple example of an action:

//..
actions: {
  increment(context) {
    context.commit('increment');
  }
}

Action handlers receive a context object as their first argument, which gives us access to store properties and methods. For example:

  • context.commit: commit a mutation
  • context.state: access state
  • context.getters: access getters

You can also use argument destructing to extract the store attributes you need for your code. For example:

actions: {
  increment({ commit }) {
    commit('increment');
  }
}

As mentioned above, actions can be asynchronous. Here’s an example:

actions: {
  incrementAsync: async({ commit }) => {
    return await setTimeout(() => { commit('increment') }, 1000);
  }
}

In this example, the mutation is committed after 1,000 milliseconds.

Like mutations, action handlers aren’t called directly, but rather via a dedicated dispatch method on the store, like so:

store.dispatch('incrementAsync')

// dispatch with payload
store.dispatch('incrementBy', { amount: 25})

// dispatch with object
store.dispatch({
  type: 'incrementBy',
  amount: 25
})

You can dispatch an action in a component like this:

this.$store.dispatch('increment')

The mapActions Helper

Alternatively, you can use the mapActions helper to assign action handlers to local methods:

import { mapActions } from  'vuex'

export default {
  //..
  methods: {
    ...mapActions([
      'incrementBy', // maps this.increment(amount) to this.$store.dispatch(increment)
      'incrementAsync', // maps this.incrementAsync() to this.$store.dispatch(incrementAsync)
      add: 'increment' // maps this.add() to this.$store.dispatch(increment)
    ])
  }
}

Re-build Counter App Using Vuex

Now that we’ve had a look at the core concepts of Vuex, it’s time to implement what we’ve learned and rewrite our counter to make use of Vue’s official state management solution.

If you fancy a challenge, you might like to have a go at doing this yourself before reading on …

When we generated our project using Vue CLI, we selected Vuex as one of the features. A couple of things happened:

  1. Vuex was installed as a package dependency. Check your package.json to confirm this.
  2. A store.js file was created and injected into your Vue.js application via main.js.

To convert our “local state” counter app to a Vuex application, open src/store.js and update the code as follows:

import Vue from 'vue'
import Vuex from 'vuex'

Vue.use(Vuex)

export default new Vuex.Store({
  state: {
    count: 0
  },
  getters: {
    parity: state => state.count % 2 === 0 ? 'even' : 'odd'
  },
  mutations: {
    increment(state) {
      state.count++;
    },
    decrement(state) {
      state.count--;
    }
  },
  actions: {
    increment: ({ commit }) => commit('increment'),
    decrement: ({ commit }) => commit('decrement'),
    incrementIfOdd: ({ commit, getters }) => getters.parity === 'odd' ? commit('increment') : false,
    incrementAsync: ({ commit }) => {
      setTimeout(() => { commit('increment') }, 1000);
    }
  }
});

Here we can see how a complete Vuex store is structured in practice. Please go back over the theory part of this article if anything here is unclear to you.

Next, update the src/components/Counter.vue component by replacing the existing code within the <script> block. We’ll switch the local state and functions to the newly created ones in the Vuex store:

import { mapState mapGetters, mapActions } from 'vuex'

export default {
  name: 'Counter',
  computed: {
    ...mapState([
      'count'
    ]),
    ...mapGetters([
      'parity'
    ])
  },
  methods: mapActions([
    'increment',
    'decrement',
    'incrementIfOdd',
    'incrementAsync'
  ])
}

The template code should remain the same, as we’re sticking to the previous variable and function names. See how much cleaner the code now is.

If you don’t want to use the state and getter map helpers, you can access the store data directly from your template like this:

<p>
  Clicked {{ $store.state.count }} times! Count is {{ $store.getters.parity }}.
</p>

After you’ve saved your changes, make sure to test your application. From an end-user perspective, the counter application should function exactly the same as before. The only difference is that the counter is now operating from a Vuex store.

Conclusion

In this article, we’ve looked at what Vuex is, what problem it solves, how to install it, as well as its core concepts. We then applied these concepts to refactor our counter app to work with Vuex. Hopefully this introduction will serve you well in implementing Vuex in your own projects.

#vue-js #javascript #web-development

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Buddha Community

 Getting Started with Vuex: A Beginner’s Guide
Shubham Ankit

Shubham Ankit

1657081614

How to Automate Excel with Python | Python Excel Tutorial (OpenPyXL)

How to Automate Excel with Python

In this article, We will show how we can use python to automate Excel . A useful Python library is Openpyxl which we will learn to do Excel Automation

What is OPENPYXL

Openpyxl is a Python library that is used to read from an Excel file or write to an Excel file. Data scientists use Openpyxl for data analysis, data copying, data mining, drawing charts, styling sheets, adding formulas, and more.

Workbook: A spreadsheet is represented as a workbook in openpyxl. A workbook consists of one or more sheets.

Sheet: A sheet is a single page composed of cells for organizing data.

Cell: The intersection of a row and a column is called a cell. Usually represented by A1, B5, etc.

Row: A row is a horizontal line represented by a number (1,2, etc.).

Column: A column is a vertical line represented by a capital letter (A, B, etc.).

Openpyxl can be installed using the pip command and it is recommended to install it in a virtual environment.

pip install openpyxl

CREATE A NEW WORKBOOK

We start by creating a new spreadsheet, which is called a workbook in Openpyxl. We import the workbook module from Openpyxl and use the function Workbook() which creates a new workbook.

from openpyxl
import Workbook
#creates a new workbook
wb = Workbook()
#Gets the first active worksheet
ws = wb.active
#creating new worksheets by using the create_sheet method

ws1 = wb.create_sheet("sheet1", 0) #inserts at first position
ws2 = wb.create_sheet("sheet2") #inserts at last position
ws3 = wb.create_sheet("sheet3", -1) #inserts at penultimate position

#Renaming the sheet
ws.title = "Example"

#save the workbook
wb.save(filename = "example.xlsx")

READING DATA FROM WORKBOOK

We load the file using the function load_Workbook() which takes the filename as an argument. The file must be saved in the same working directory.

#loading a workbook
wb = openpyxl.load_workbook("example.xlsx")

 

GETTING SHEETS FROM THE LOADED WORKBOOK

 

#getting sheet names
wb.sheetnames
result = ['sheet1', 'Sheet', 'sheet3', 'sheet2']

#getting a particular sheet
sheet1 = wb["sheet2"]

#getting sheet title
sheet1.title
result = 'sheet2'

#Getting the active sheet
sheetactive = wb.active
result = 'sheet1'

 

ACCESSING CELLS AND CELL VALUES

 

#get a cell from the sheet
sheet1["A1"] <
  Cell 'Sheet1'.A1 >

  #get the cell value
ws["A1"].value 'Segment'

#accessing cell using row and column and assigning a value
d = ws.cell(row = 4, column = 2, value = 10)
d.value
10

 

ITERATING THROUGH ROWS AND COLUMNS

 

#looping through each row and column
for x in range(1, 5):
  for y in range(1, 5):
  print(x, y, ws.cell(row = x, column = y)
    .value)

#getting the highest row number
ws.max_row
701

#getting the highest column number
ws.max_column
19

There are two functions for iterating through rows and columns.

Iter_rows() => returns the rows
Iter_cols() => returns the columns {
  min_row = 4, max_row = 5, min_col = 2, max_col = 5
} => This can be used to set the boundaries
for any iteration.

Example:

#iterating rows
for row in ws.iter_rows(min_row = 2, max_col = 3, max_row = 3):
  for cell in row:
  print(cell) <
  Cell 'Sheet1'.A2 >
  <
  Cell 'Sheet1'.B2 >
  <
  Cell 'Sheet1'.C2 >
  <
  Cell 'Sheet1'.A3 >
  <
  Cell 'Sheet1'.B3 >
  <
  Cell 'Sheet1'.C3 >

  #iterating columns
for col in ws.iter_cols(min_row = 2, max_col = 3, max_row = 3):
  for cell in col:
  print(cell) <
  Cell 'Sheet1'.A2 >
  <
  Cell 'Sheet1'.A3 >
  <
  Cell 'Sheet1'.B2 >
  <
  Cell 'Sheet1'.B3 >
  <
  Cell 'Sheet1'.C2 >
  <
  Cell 'Sheet1'.C3 >

To get all the rows of the worksheet we use the method worksheet.rows and to get all the columns of the worksheet we use the method worksheet.columns. Similarly, to iterate only through the values we use the method worksheet.values.


Example:

for row in ws.values:
  for value in row:
  print(value)

 

WRITING DATA TO AN EXCEL FILE

Writing to a workbook can be done in many ways such as adding a formula, adding charts, images, updating cell values, inserting rows and columns, etc… We will discuss each of these with an example.

 

CREATING AND SAVING A NEW WORKBOOK

 

#creates a new workbook
wb = openpyxl.Workbook()

#saving the workbook
wb.save("new.xlsx")

 

ADDING AND REMOVING SHEETS

 

#creating a new sheet
ws1 = wb.create_sheet(title = "sheet 2")

#creating a new sheet at index 0
ws2 = wb.create_sheet(index = 0, title = "sheet 0")

#checking the sheet names
wb.sheetnames['sheet 0', 'Sheet', 'sheet 2']

#deleting a sheet
del wb['sheet 0']

#checking sheetnames
wb.sheetnames['Sheet', 'sheet 2']

 

ADDING CELL VALUES

 

#checking the sheet value
ws['B2'].value
null

#adding value to cell
ws['B2'] = 367

#checking value
ws['B2'].value
367

 

ADDING FORMULAS

 

We often require formulas to be included in our Excel datasheet. We can easily add formulas using the Openpyxl module just like you add values to a cell.
 

For example:

import openpyxl
from openpyxl
import Workbook

wb = openpyxl.load_workbook("new1.xlsx")
ws = wb['Sheet']

ws['A9'] = '=SUM(A2:A8)'

wb.save("new2.xlsx")

The above program will add the formula (=SUM(A2:A8)) in cell A9. The result will be as below.

image

 

MERGE/UNMERGE CELLS

Two or more cells can be merged to a rectangular area using the method merge_cells(), and similarly, they can be unmerged using the method unmerge_cells().

For example:
Merge cells

#merge cells B2 to C9
ws.merge_cells('B2:C9')
ws['B2'] = "Merged cells"

Adding the above code to the previous example will merge cells as below.

image

UNMERGE CELLS

 

#unmerge cells B2 to C9
ws.unmerge_cells('B2:C9')

The above code will unmerge cells from B2 to C9.

INSERTING AN IMAGE

To insert an image we import the image function from the module openpyxl.drawing.image. We then load our image and add it to the cell as shown in the below example.

Example:

import openpyxl
from openpyxl
import Workbook
from openpyxl.drawing.image
import Image

wb = openpyxl.load_workbook("new1.xlsx")
ws = wb['Sheet']
#loading the image(should be in same folder)
img = Image('logo.png')
ws['A1'] = "Adding image"
#adjusting size
img.height = 130
img.width = 200
#adding img to cell A3

ws.add_image(img, 'A3')

wb.save("new2.xlsx")

Result:

image

CREATING CHARTS

Charts are essential to show a visualization of data. We can create charts from Excel data using the Openpyxl module chart. Different forms of charts such as line charts, bar charts, 3D line charts, etc., can be created. We need to create a reference that contains the data to be used for the chart, which is nothing but a selection of cells (rows and columns). I am using sample data to create a 3D bar chart in the below example:

Example

import openpyxl
from openpyxl
import Workbook
from openpyxl.chart
import BarChart3D, Reference, series

wb = openpyxl.load_workbook("example.xlsx")
ws = wb.active

values = Reference(ws, min_col = 3, min_row = 2, max_col = 3, max_row = 40)
chart = BarChart3D()
chart.add_data(values)
ws.add_chart(chart, "E3")
wb.save("MyChart.xlsx")

Result
image


How to Automate Excel with Python with Video Tutorial

Welcome to another video! In this video, We will cover how we can use python to automate Excel. I'll be going over everything from creating workbooks to accessing individual cells and stylizing cells. There is a ton of things that you can do with Excel but I'll just be covering the core/base things in OpenPyXl.

⭐️ Timestamps ⭐️
00:00 | Introduction
02:14 | Installing openpyxl
03:19 | Testing Installation
04:25 | Loading an Existing Workbook
06:46 | Accessing Worksheets
07:37 | Accessing Cell Values
08:58 | Saving Workbooks
09:52 | Creating, Listing and Changing Sheets
11:50 | Creating a New Workbook
12:39 | Adding/Appending Rows
14:26 | Accessing Multiple Cells
20:46 | Merging Cells
22:27 | Inserting and Deleting Rows
23:35 | Inserting and Deleting Columns
24:48 | Copying and Moving Cells
26:06 | Practical Example, Formulas & Cell Styling

📄 Resources 📄
OpenPyXL Docs: https://openpyxl.readthedocs.io/en/stable/ 
Code Written in This Tutorial: https://github.com/techwithtim/ExcelPythonTutorial 
Subscribe: https://www.youtube.com/c/TechWithTim/featured 

#python 

Mike  Kozey

Mike Kozey

1656151740

Test_cov_console: Flutter Console Coverage Test

Flutter Console Coverage Test

This small dart tools is used to generate Flutter Coverage Test report to console

How to install

Add a line like this to your package's pubspec.yaml (and run an implicit flutter pub get):

dev_dependencies:
  test_cov_console: ^0.2.2

How to run

run the following command to make sure all flutter library is up-to-date

flutter pub get
Running "flutter pub get" in coverage...                            0.5s

run the following command to generate lcov.info on coverage directory

flutter test --coverage
00:02 +1: All tests passed!

run the tool to generate report from lcov.info

flutter pub run test_cov_console
---------------------------------------------|---------|---------|---------|-------------------|
File                                         |% Branch | % Funcs | % Lines | Uncovered Line #s |
---------------------------------------------|---------|---------|---------|-------------------|
lib/src/                                     |         |         |         |                   |
 print_cov.dart                              |  100.00 |  100.00 |   88.37 |...,149,205,206,207|
 print_cov_constants.dart                    |    0.00 |    0.00 |    0.00 |    no unit testing|
lib/                                         |         |         |         |                   |
 test_cov_console.dart                       |    0.00 |    0.00 |    0.00 |    no unit testing|
---------------------------------------------|---------|---------|---------|-------------------|
 All files with unit testing                 |  100.00 |  100.00 |   88.37 |                   |
---------------------------------------------|---------|---------|---------|-------------------|

Optional parameter

If not given a FILE, "coverage/lcov.info" will be used.
-f, --file=<FILE>                      The target lcov.info file to be reported
-e, --exclude=<STRING1,STRING2,...>    A list of contains string for files without unit testing
                                       to be excluded from report
-l, --line                             It will print Lines & Uncovered Lines only
                                       Branch & Functions coverage percentage will not be printed
-i, --ignore                           It will not print any file without unit testing
-m, --multi                            Report from multiple lcov.info files
-c, --csv                              Output to CSV file
-o, --output=<CSV-FILE>                Full path of output CSV file
                                       If not given, "coverage/test_cov_console.csv" will be used
-t, --total                            Print only the total coverage
                                       Note: it will ignore all other option (if any), except -m
-p, --pass=<MINIMUM>                   Print only the whether total coverage is passed MINIMUM value or not
                                       If the value >= MINIMUM, it will print PASSED, otherwise FAILED
                                       Note: it will ignore all other option (if any), except -m
-h, --help                             Show this help

example run the tool with parameters

flutter pub run test_cov_console --file=coverage/lcov.info --exclude=_constants,_mock
---------------------------------------------|---------|---------|---------|-------------------|
File                                         |% Branch | % Funcs | % Lines | Uncovered Line #s |
---------------------------------------------|---------|---------|---------|-------------------|
lib/src/                                     |         |         |         |                   |
 print_cov.dart                              |  100.00 |  100.00 |   88.37 |...,149,205,206,207|
lib/                                         |         |         |         |                   |
 test_cov_console.dart                       |    0.00 |    0.00 |    0.00 |    no unit testing|
---------------------------------------------|---------|---------|---------|-------------------|
 All files with unit testing                 |  100.00 |  100.00 |   88.37 |                   |
---------------------------------------------|---------|---------|---------|-------------------|

report for multiple lcov.info files (-m, --multi)

It support to run for multiple lcov.info files with the followings directory structures:
1. No root module
<root>/<module_a>
<root>/<module_a>/coverage/lcov.info
<root>/<module_a>/lib/src
<root>/<module_b>
<root>/<module_b>/coverage/lcov.info
<root>/<module_b>/lib/src
...
2. With root module
<root>/coverage/lcov.info
<root>/lib/src
<root>/<module_a>
<root>/<module_a>/coverage/lcov.info
<root>/<module_a>/lib/src
<root>/<module_b>
<root>/<module_b>/coverage/lcov.info
<root>/<module_b>/lib/src
...
You must run test_cov_console on <root> dir, and the report would be grouped by module, here is
the sample output for directory structure 'with root module':
flutter pub run test_cov_console --file=coverage/lcov.info --exclude=_constants,_mock --multi
---------------------------------------------|---------|---------|---------|-------------------|
File                                         |% Branch | % Funcs | % Lines | Uncovered Line #s |
---------------------------------------------|---------|---------|---------|-------------------|
lib/src/                                     |         |         |         |                   |
 print_cov.dart                              |  100.00 |  100.00 |   88.37 |...,149,205,206,207|
lib/                                         |         |         |         |                   |
 test_cov_console.dart                       |    0.00 |    0.00 |    0.00 |    no unit testing|
---------------------------------------------|---------|---------|---------|-------------------|
 All files with unit testing                 |  100.00 |  100.00 |   88.37 |                   |
---------------------------------------------|---------|---------|---------|-------------------|
---------------------------------------------|---------|---------|---------|-------------------|
File - module_a -                            |% Branch | % Funcs | % Lines | Uncovered Line #s |
---------------------------------------------|---------|---------|---------|-------------------|
lib/src/                                     |         |         |         |                   |
 print_cov.dart                              |  100.00 |  100.00 |   88.37 |...,149,205,206,207|
lib/                                         |         |         |         |                   |
 test_cov_console.dart                       |    0.00 |    0.00 |    0.00 |    no unit testing|
---------------------------------------------|---------|---------|---------|-------------------|
 All files with unit testing                 |  100.00 |  100.00 |   88.37 |                   |
---------------------------------------------|---------|---------|---------|-------------------|
---------------------------------------------|---------|---------|---------|-------------------|
File - module_b -                            |% Branch | % Funcs | % Lines | Uncovered Line #s |
---------------------------------------------|---------|---------|---------|-------------------|
lib/src/                                     |         |         |         |                   |
 print_cov.dart                              |  100.00 |  100.00 |   88.37 |...,149,205,206,207|
lib/                                         |         |         |         |                   |
 test_cov_console.dart                       |    0.00 |    0.00 |    0.00 |    no unit testing|
---------------------------------------------|---------|---------|---------|-------------------|
 All files with unit testing                 |  100.00 |  100.00 |   88.37 |                   |
---------------------------------------------|---------|---------|---------|-------------------|

Output to CSV file (-c, --csv, -o, --output)

flutter pub run test_cov_console -c --output=coverage/test_coverage.csv

#### sample CSV output file:
File,% Branch,% Funcs,% Lines,Uncovered Line #s
lib/,,,,
test_cov_console.dart,0.00,0.00,0.00,no unit testing
lib/src/,,,,
parser.dart,100.00,100.00,97.22,"97"
parser_constants.dart,100.00,100.00,100.00,""
print_cov.dart,100.00,100.00,82.91,"29,49,51,52,171,174,177,180,183,184,185,186,187,188,279,324,325,387,388,389,390,391,392,393,394,395,398"
print_cov_constants.dart,0.00,0.00,0.00,no unit testing
All files with unit testing,100.00,100.00,86.07,""

Installing

Use this package as an executable

Install it

You can install the package from the command line:

dart pub global activate test_cov_console

Use it

The package has the following executables:

$ test_cov_console

Use this package as a library

Depend on it

Run this command:

With Dart:

 $ dart pub add test_cov_console

With Flutter:

 $ flutter pub add test_cov_console

This will add a line like this to your package's pubspec.yaml (and run an implicit dart pub get):

dependencies:
  test_cov_console: ^0.2.2

Alternatively, your editor might support dart pub get or flutter pub get. Check the docs for your editor to learn more.

Import it

Now in your Dart code, you can use:

import 'package:test_cov_console/test_cov_console.dart';

example/lib/main.dart

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
        // This makes the visual density adapt to the platform that you run
        // the app on. For desktop platforms, the controls will be smaller and
        // closer together (more dense) than on mobile platforms.
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key? key, required this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

Author: DigitalKatalis
Source Code: https://github.com/DigitalKatalis/test_cov_console 
License: BSD-3-Clause license

#flutter #dart #test 

Abigail betty

Abigail betty

1624226400

What is Bitcoin Cash? - A Beginner’s Guide

Bitcoin Cash was created as a result of a hard fork in the Bitcoin network. The Bitcoin Cash network supports a larger block size than Bitcoin (currently 32mb as opposed to Bitcoin’s 1mb).

Later on, Bitcoin Cash forked into Bitcoin SV due to differences in how to carry on its developments.

That’s Bitcoin Cash in a nutshell. If you want a more detailed review watch the complete video. Here’s what I’ll cover:

0:50 - Bitcoin forks
2:06 - Bitcoin’s block size debate
3:35 - Big blocks camp
4:26 - Small blocks camp
5:16 - Small blocks vs. big blocks arguments
7:05 - How decisions are made in the Bitcoin network
10:14 - Block size debate resolution
11:06 - Bitcoin cash intro
11:28 - BTC vs. BCH
12:13 - Bitcoin Cash (ABC) vs. Bitcoin SV
13:09 - Conclusion
📺 The video in this post was made by 99Bitcoins
The origin of the article: https://www.youtube.com/watch?v=ONhbb4YVRLM
🔺 DISCLAIMER: The article is for information sharing. The content of this video is solely the opinions of the speaker who is not a licensed financial advisor or registered investment advisor. Not investment advice or legal advice.
Cryptocurrency trading is VERY risky. Make sure you understand these risks and that you are responsible for what you do with your money
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Thanks for visiting and watching! Please don’t forget to leave a like, comment and share!

#bitcoin #blockchain #bitcoin cash #what is bitcoin cash? - a beginner’s guide #what is bitcoin cash #a beginner’s guide

Monty  Boehm

Monty Boehm

1659453850

Twitter.jl: Julia Package to Access Twitter API

Twitter.jl

A Julia package for interacting with the Twitter API.

Twitter.jl is a Julia package to work with the Twitter API v1.1. Currently, only the REST API methods are supported; streaming API endpoints aren't implemented at this time.

All functions have required arguments for those parameters required by Twitter and an options keyword argument to provide a Dict{String, String} of optional parameters Twitter API documentation. Most function calls will return either a Dict or an Array <: TwitterType. Bad requests will return the response code from the API (403, 404, etc).

DataFrame methods are defined for functions returning composite types: Tweets, Places, Lists, and Users.

Authentication

Before one can make use of this package, you must create an application on the Twitter's Developer Platform.

Once your application is approved, you can access your dashboard/portal to grab your authentication credentials from the "Details" tab of the application.

Note that you will also want to ensure that your App has Read / Write OAuth access in order to post tweets. You can find out more about this on Stack Overflow.

Installation

To install this package, enter ] on the REPL to bring up Julia's package manager. Then add the package:

julia> ]
(v1.7) pkg> add Twitter

Tip: Press Ctrl+C to return to the julia> prompt.

Usage

To run Twitter.jl, enter the following command in your Julia REPL

julia> using Twitter

Then the a global variable has to be declared with the twitterauth function. This function holds the consumer_key(API Key), consumer_secret(API Key Secret), oauth_token(Access Token), and oauth_secret(Access Token Secret) respectively.

twitterauth("6nOtpXmf...", # API Key
            "sES5Zlj096S...", # API Key Secret
            "98689850-Hj...", # Access Token
            "UroqCVpWKIt...") # Access Token Secret
  • Ensure you put your credentials in an env file to avoid pushing your secrets to the public 🙀.

Note: This package does not currently support OAuth authentication.

Code examples

See runtests.jl for example function calls.

using Twitter, Test
using JSON, OAuth

# set debugging
ENV["JULIA_DEBUG"]=Twitter

twitterauth(ENV["CONSUMER_KEY"], ENV["CONSUMER_SECRET"], ENV["ACCESS_TOKEN"], ENV["ACCESS_TOKEN_SECRET"])

#get_mentions_timeline
mentions_timeline_default = get_mentions_timeline()
tw = mentions_timeline_default[1]
tw_df = DataFrame(mentions_timeline_default)
@test 0 <= length(mentions_timeline_default) <= 20
@test typeof(mentions_timeline_default) == Vector{Tweets}
@test typeof(tw) == Tweets
@test size(tw_df)[2] == 30

#get_user_timeline
user_timeline_default = get_user_timeline(screen_name = "randyzwitch")
@test typeof(user_timeline_default) == Vector{Tweets}

#get_home_timeline
home_timeline_default = get_home_timeline()
@test typeof(home_timeline_default) == Vector{Tweets}

#get_single_tweet_id
get_tweet_by_id = get_single_tweet_id(id = "434685122671939584")
@test typeof(get_tweet_by_id) == Tweets

#get_search_tweets
duke_tweets = get_search_tweets(q = "#Duke", count = 200)
@test typeof(duke_tweets) <: Dict

#test sending/deleting direct messages
#commenting out because Twitter API changed. Come back to fix
# send_dm = post_direct_messages_send(text = "Testing from Julia, this might disappear later $(time())", screen_name = "randyzwitch")
# get_single_dm = get_direct_messages_show(id = send_dm.id)
# destroy = post_direct_messages_destroy(id = send_dm.id)
# @test typeof(send_dm) == Tweets
# @test typeof(get_single_dm) == Tweets
# @test typeof(destroy) == Tweets

#creating/destroying friendships
add_friend = post_friendships_create(screen_name = "kyrieirving")

unfollow = post_friendships_destroy(screen_name = "kyrieirving")
unfollow_df = DataFrame(unfollow)
@test typeof(add_friend) == Users
@test typeof(unfollow) == Users
@test size(unfollow_df)[2] == 40

# create a cursor for follower ids
follow_cursor_test = get_followers_ids(screen_name = "twitter", count = 10_000)
@test length(follow_cursor_test["ids"]) == 10_000

# create a cursor for friend ids - use barackobama because he follows a lot of accounts!
friend_cursor_test = get_friends_ids(screen_name = "BarackObama", count = 10_000)
@test length(friend_cursor_test["ids"]) == 10_000

# create a test for home timelines
home_t = get_home_timeline(count = 2)
@test length(home_t) > 1

# TEST of cursoring functionality on user timelines
user_t = get_user_timeline(screen_name = "stefanjwojcik", count = 400)
@test length(user_t) == 400
# get the minimum ID of the tweets returned (the earliest)
minid = minimum(x.id for x in user_t);

# now iterate until you hit that tweet: should return 399
# WARNING: current versions of julia cannot use keywords in macros? read here: https://github.com/JuliaLang/julia/pull/29261
# eventually replace since_id = minid
tweets_since = get_user_timeline(screen_name = "stefanjwojcik", count = 400, since_id = 1001808621053898752, include_rts=1)

@test length(tweets_since)>=399

# testing get_mentions_timeline
mentions = get_mentions_timeline(screen_name = "stefanjwojcik", count = 300) 
@test length(mentions) >= 50 #sometimes API doesn't return number requested (twitter API specifies count is the max returned, may be much lower)
@test Tweets<:typeof(mentions[1])

# testing retweets_of_me
my_rts = get_retweets_of_me(count = 300)
@test Tweets<:typeof(my_rts[1])

Want to contribute?

Contributions are welcome! Kindly refer to the contribution guidelines.

Linux: Build Status 

CodeCov: codecov

Author: Randyzwitch
Source Code: https://github.com/randyzwitch/Twitter.jl 
License: View license

#julia #api #twitter 

Micheal  Block

Micheal Block

1600671600

Start-off with Streamlit(Beginner’s Approach)

Streamlit is an open-source app framework** that **isthe easiest way for data scientists and machine learning engineers to create beautiful, performant apps in only a few hours!

By the end of this blog, you are going to be comfortable with using Streamlit to build a basic streamlit web-application.

#beginner #tutorial #beginners-guide #web-app-development #streamlit