Random Walk: Will the Drunk Man Fall Off the Cliff?

A drunk man standing on a cliff, takes steps randomly left and right. Each step he takes has a probability of going left and a probability of going right and the size of each step is same. If the drunk man is allowed to randomly step indefinitely, what will be the probability that he falls off the cliff?

Any guesses? Well, let’s again have a glimpse of this problem through “Random Walk”.

---

The Random Walk theory is based on the irregular motion of the individual pollen particles, studied by botanist, Mr. Robert Brown in 1828. In the process of researching on a random walk, scientists like Einstein and Smoluchowski studied similar subjects like random process, random noise, spectral analysis, and stochastic equations. The first simple model of Random Walk proposed was uncorrelated and unbiased.

• Uncorrelated means the direction of movement is completely independent of the previous directions taken.
• **_Unbiased _**means there is no preferred direction, the direction moved at each step is completely random.

“A random walk is a mathematical object, known as a stochastic or random process, that describes a path that consists of a succession of random steps on some mathematical space such as the integers.” (Source: Wikipedia)

It is a problem, which is closely related to Brownian motion.

Types of Random Walks

1. Correlated Random Walks (CRWs)

It involves a correlation between successive step orientations. This correlation is termed as **Persistence_. _**This produces a local directional bias, each step tends to point in the same direction as the previous one, although the influence of the initial direction of motion progressively diminishes over time and step, orientations are uniformly distributed in the long term. The nature of the motion of animals is similar, hence, CRWs have been constantly used to monitor motion paths of animals in various contexts.

#random-walk #data-science #gaussian-distribution #statistics #random #data analysis

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Buddha Community

Random Walk: Will the Drunk Man Fall Off the Cliff?

A drunk man standing on a cliff, takes steps randomly left and right. Each step he takes has a probability of going left and a probability of going right and the size of each step is same. If the drunk man is allowed to randomly step indefinitely, what will be the probability that he falls off the cliff?

Any guesses? Well, let’s again have a glimpse of this problem through “Random Walk”.

---

The Random Walk theory is based on the irregular motion of the individual pollen particles, studied by botanist, Mr. Robert Brown in 1828. In the process of researching on a random walk, scientists like Einstein and Smoluchowski studied similar subjects like random process, random noise, spectral analysis, and stochastic equations. The first simple model of Random Walk proposed was uncorrelated and unbiased.

• Uncorrelated means the direction of movement is completely independent of the previous directions taken.
• **_Unbiased _**means there is no preferred direction, the direction moved at each step is completely random.

“A random walk is a mathematical object, known as a stochastic or random process, that describes a path that consists of a succession of random steps on some mathematical space such as the integers.” (Source: Wikipedia)

It is a problem, which is closely related to Brownian motion.

Types of Random Walks

1. Correlated Random Walks (CRWs)

It involves a correlation between successive step orientations. This correlation is termed as **Persistence_. _**This produces a local directional bias, each step tends to point in the same direction as the previous one, although the influence of the initial direction of motion progressively diminishes over time and step, orientations are uniformly distributed in the long term. The nature of the motion of animals is similar, hence, CRWs have been constantly used to monitor motion paths of animals in various contexts.

#random-walk #data-science #gaussian-distribution #statistics #random #data analysis

HAML Lint: Tool For Writing Clean and Consistent HAML

HAML-Lint

haml-lint is a tool to help keep your HAML files clean and readable. In addition to HAML-specific style and lint checks, it integrates with RuboCop to bring its powerful static analysis tools to your HAML documents.

You can run haml-lint manually from the command line, or integrate it into your SCM hooks.

Requirements

• Ruby 2.4+
• HAML 4.0+

Installation

gem install haml_lint

If you'd rather install haml-lint using bundler, don't require it in your Gemfile:

gem 'haml_lint', require: false

Then you can still use haml-lint from the command line, but its source code won't be auto-loaded inside your application.

Usage

Run haml-lint from the command line by passing in a directory (or multiple directories) to recursively scan:

haml-lint app/views/

You can also specify a list of files explicitly:

haml-lint app/**/*.html.haml

haml-lint will output any problems with your HAML, including the offending filename and line number.

File Encoding

haml-lint assumes all files are encoded in UTF-8.

Command Line Flags

Command Line Flag	Description
--auto-gen-config	Generate a configuration file acting as a TODO list
--auto-gen-exclude-limit	Number of failures to allow in the TODO list before the entire rule is excluded
-c/--config	Specify which configuration file to use
-e/--exclude	Exclude one or more files from being linted
-i/--include-linter	Specify which linters you specifically want to run
-x/--exclude-linter	Specify which linters you don't want to run
-r/--reporter	Specify which reporter you want to use to generate the output
-p/--parallel	Run linters in parallel using available CPUs
--fail-fast	Specify whether to fail after the first file with lint
--fail-level	Specify the minimum severity (warning or error) for which the lint should fail
--[no-]color	Whether to output in color
--[no-]summary	Whether to output a summary in the default reporter
--show-linters	Show all registered linters
--show-reporters	Display available reporters
-h/--help	Show command line flag documentation
-v/--version	Show haml-lint version
-V/--verbose-version	Show haml-lint, haml, and ruby version information

Configuration

haml-lint will automatically recognize and load any file with the name .haml-lint.yml as a configuration file. It loads the configuration based on the directory haml-lint is being run from, ascending until a configuration file is found. Any configuration loaded is automatically merged with the default configuration (see config/default.yml).

Here's an example configuration file:

linters:
  ImplicitDiv:
    enabled: false
    severity: error

  LineLength:
    max: 100

All linters have an enabled option which can be true or false, which controls whether the linter is run, along with linter-specific options. The defaults are defined in config/default.yml.

Linter Options

Option	Description
enabled	If false, this linter will never be run. This takes precedence over any other option.
include	List of files or glob patterns to scope this linter to. This narrows down any files specified via the command line.
exclude	List of files or glob patterns to exclude from this linter. This excludes any files specified via the command line or already filtered via the include option.
severity	The severity of the linter. External tools consuming haml-lint output can use this to determine whether to warn or error based on the lints reported.

Global File Exclusion

The exclude global configuration option allows you to specify a list of files or glob patterns to exclude from all linters. This is useful for ignoring third-party code that you don't maintain or care to lint. You can specify a single string or a list of strings for this option.

Skipping Frontmatter

Some static blog generators such as Jekyll include leading frontmatter to the template for their own tracking purposes. haml-lint allows you to ignore these headers by specifying the skip_frontmatter option in your .haml-lint.yml configuration:

skip_frontmatter: true

Inheriting from Other Configuration Files

The inherits_from global configuration option allows you to specify an inheritance chain for a configuration file. It accepts either a scalar value of a single file name or a vector of multiple files to inherit from. The inherited files are resolved in a first in, first out order and with "last one wins" precedence. For example:

inherits_from:
  - .shared_haml-lint.yml
  - .personal_haml-lint.yml

First, the default configuration is loaded. Then the .shared_haml-lint.yml configuration is loaded, followed by .personal_haml-lint.yml. Each of these overwrite each other in the event of a collision in configuration value. Once the inheritance chain is resolved, the base configuration is loaded and applies its rules to overwrite any in the intermediate configuration.

Lastly, in order to match your RuboCop configuration style, you can also use the inherit_from directive, which is an alias for inherits_from.

Linters

» Linters Documentation

haml-lint is an opinionated tool that helps you enforce a consistent style in your HAML files. As an opinionated tool, we've had to make calls about what we think are the "best" style conventions, even when there are often reasonable arguments for more than one possible style. While all of our choices have a rational basis, we think that the opinions themselves are less important than the fact that haml-lint provides us with an automated and low-cost means of enforcing consistency.

Custom Linters

Add the following to your configuration file:

require:
  - './relative/path/to/my_first_linter.rb'
  - 'absolute/path/to/my_second_linter.rb'

The files that are referenced by this config should have the following structure:

module HamlLint
  # MyFirstLinter is the name of the linter in this example, but it can be anything
  class Linter::MyFirstLinter < Linter
    include LinterRegistry

    def visit_tag
      return unless node.tag_name == 'div'
      record_lint(node, "You're not allowed divs!")
    end
  end
end

For more information on the different types on HAML node, please look through the HAML parser code: https://github.com/haml/haml/blob/master/lib/haml/parser.rb

Keep in mind that by default your linter will be disabled by default. So you will need to enable it in your configuration file to have it run.

Disabling Linters within Source Code

One or more individual linters can be disabled locally in a file by adding a directive comment. These comments look like the following:

-# haml-lint:disable AltText, LineLength
[...]
-# haml-lint:enable AltText, LineLength

You can disable all linters for a section with the following:

-# haml-lint:disable all

Directive Scope

A directive will disable the given linters for the scope of the block. This scope is inherited by child elements and sibling elements that come after the comment. For example:

-# haml-lint:disable AltText
#content
  %img#will-not-show-lint-1{ src: "will-not-show-lint-1.png" }
  -# haml-lint:enable AltText
  %img#will-show-lint-1{ src: "will-show-lint-1.png" }
  .sidebar
    %img#will-show-lint-2{ src: "will-show-lint-2.png" }
%img#will-not-show-lint-2{ src: "will-not-show-lint-2.png" }

The #will-not-show-lint-1 image on line 2 will not raise an AltText lint because of the directive on line 1. Since that directive is at the top level of the tree, it applies everywhere.

However, on line 4, the directive enables the AltText linter for the remainder of the #content element's content. This means that the #will-show-lint-1 image on line 5 will raise an AltText lint because it is a sibling of the enabling directive that appears later in the #content element. Likewise, the #will-show-lint-2 image on line 7 will raise an AltText lint because it is a child of a sibling of the enabling directive.

Lastly, the #will-not-show-lint-2 image on line 8 will not raise an AltText lint because the enabling directive on line 4 exists in a separate element and is not a sibling of the it.

Directive Precedence

If there are multiple directives for the same linter in an element, the last directive wins. For example:

-# haml-lint:enable AltText
%p Hello, world!
-# haml-lint:disable AltText
%img#will-not-show-lint{ src: "will-not-show-lint.png" }

There are two conflicting directives for the AltText linter. The first one enables it, but the second one disables it. Since the disable directive came later, the #will-not-show-lint element will not raise an AltText lint.

You can use this functionality to selectively enable directives within a file by first using the haml-lint:disable all directive to disable all linters in the file, then selectively using haml-lint:enable to enable linters one at a time.

Onboarding Onto a Preexisting Project

Adding a new linter into a project that wasn't previously using one can be a daunting task. To help ease the pain of starting to use Haml-Lint, you can generate a configuration file that will exclude all linters from reporting lint in files that currently have lint. This gives you something similar to a to-do list where the violations that you had when you started using Haml-Lint are listed for you to whittle away, but ensuring that any views you create going forward are properly linted.

To use this functionality, call Haml-Lint like:

haml-lint --auto-gen-config

This will generate a .haml-lint_todo.yml file that contains all existing lint as exclusions. You can then add inherits_from: .haml-lint_todo.yml to your .haml-lint.yml configuration file to ensure these exclusions are used whenever you call haml-lint.

By default, any rules with more than 15 violations will be disabled in the todo-file. You can increase this limit with the auto-gen-exclude-limit option:

haml-lint --auto-gen-config --auto-gen-exclude-limit 100

Editor Integration

Vim

If you use vim, you can have haml-lint automatically run against your HAML files after saving by using the Syntastic plugin. If you already have the plugin, just add let g:syntastic_haml_checkers = ['haml_lint'] to your .vimrc.

Vim 8 / Neovim

If you use vim 8+ or Neovim, you can have haml-lint automatically run against your HAML files as you type by using the Asynchronous Lint Engine (ALE) plugin. ALE will automatically lint your HAML files if it detects haml-lint in your PATH.

Sublime Text 3

If you use SublimeLinter 3 with Sublime Text 3 you can install the SublimeLinter-haml-lint plugin using Package Control.

Atom

If you use atom, you can install the linter-haml plugin.

TextMate 2

If you use TextMate 2, you can install the Haml-Lint.tmbundle bundle.

Visual Studio Code

If you use Visual Studio Code, you can install the Haml Lint extension

Git Integration

If you'd like to integrate haml-lint into your Git workflow, check out our Git hook manager, overcommit.

Rake Integration

To execute haml-lint via a Rake task, make sure you have rake included in your gem path (e.g. via Gemfile) add the following to your Rakefile:

require 'haml_lint/rake_task'

HamlLint::RakeTask.new

By default, when you execute rake haml_lint, the above configuration is equivalent to running haml-lint ., which will lint all .haml files in the current directory and its descendants.

You can customize your task by writing:

require 'haml_lint/rake_task'

HamlLint::RakeTask.new do |t|
  t.config = 'custom/config.yml'
  t.files = ['app/views', 'custom/*.haml']
  t.quiet = true # Don't display output from haml-lint to STDOUT
end

You can also use this custom configuration with a set of files specified via the command line:

# Single quotes prevent shell glob expansion
rake 'haml_lint[app/views, custom/*.haml]'

Files specified in this manner take precedence over the task's files attribute.

Documentation

Code documentation is generated with YARD and hosted by RubyDoc.info.

Contributing

We love getting feedback with or without pull requests. If you do add a new feature, please add tests so that we can avoid breaking it in the future.

Speaking of tests, we use Appraisal to test against both HAML 4 and 5. We use rspec to write our tests. To run the test suite, execute the following from the root directory of the repository:

appraisal bundle install
appraisal bundle exec rspec

Community

All major discussion surrounding HAML-Lint happens on the GitHub issues page.

Changelog

If you're interested in seeing the changes and bug fixes between each version of haml-lint, read the HAML-Lint Changelog.

Author: sds
Source Code: https://github.com/sds/haml-lint
License: MIT license

#haml #lint 

Generate Random Numbers in Python

There are two types of random number generators: pseudo-random number generator and true random number generator.

Pseudorandom numbers depend on computer algorithms. The computer uses algorithms to generate random numbers. These random numbers are not truly random because they are predictable like the generated numbers using NumPy random seed.

Whereas, truly random numbers are generated by measuring truly physical random parameters so we can ensure that the generated numbers are truly random.

The pseudo-random numbers are not safe to use in cryptography because they can be guessed by attackers.

In Python, the built-in random module generates pseudo-random numbers. In this tutorial, we will discuss both types. So let’s get started.

Table of Contents

• Random number between 0 and 100
• Random number with a step size
• Random floating/double number in a range
• Random number from Iterable
• Using random.choice()
• Using randint()
• Using randrange()
• Excluding certain numbers from a range (Conditional choice)
• Random number of length N
• Random numbers in a two-dimensional array
• Random number probability
• Mean and standard deviation
• Negative random number
• Generate with duplicates
• Using randrange()
• Using choice()
• Generate without duplicates (Unique random numbers)
• Random number on circle
• Shuffle Numbers
• Generate true random number

#python #random #generate random numbers #random numbers #generate random numbers in python

Amplify your dog walking service business with the uber for dog walking app

The advanced technology not just benefits businesses and users, but it also helps pets to avail the services in the app built with the latest technologies. The app is the one-stop solution for all the problems happening in everyday lives. Since people are in a busy lifestyle, they don’t get time to take care of their dogs. It is quite challenging for them to find the best and trustworthy dog walker taking full responsibility. For such issues, we have an on demand pet sitting app that helps dog walkers earn money and, at the same time, satisfies dog owners’ long demand.

Stats Report
Just like kids, pets are a part of the family for dog lovers. So, they need dog sitters and walkers to take care of them as dog owners don’t find enough time to take them out for a walk. With the increasing number of dog owners, the relevance and demand of a dog walking app is also increasing. The Reports and market metrics highlight that about 68% of households in the U.S have dogs.

We will discuss how to tap into this field by developing an app for dog walking for budding entrepreneurs.

Read More : https://www.appdupe.com/blog/amplify-your-dog-walking-service-business-with-the-uber-for-dog-walking-app/

#on-demand dog walking app #dog walking service app script #on-demand pet sitting app #on demand dog walking app development #uber for dog walking app development

Where Does Your Organization Fall On the Data Literacy Curve?

We are awash in data. “Big data” is too small of a description. By 2025 an estimated 463 exabytes of data will be created globally each day.

Well aware of this, companies are ramping up their abilities to analyze data to make good decisions. A 2020 Research and Markets report put global spending on big data analytics at $180 billion, and a New Vantage Partners 2021 survey of executives said 92% say the pace of investment is accelerating, up from 40% the prior year.

Yet investing more money isn’t resulting in an equal return in results. Long-term progress on corporate data initiatives has declined, according to the New Vantage Partners study. Cultural challenges persist.

But balancing your employees’ knowledge of data while providing them the right tools to make the best use of that data plays a role, too. To move your organization forward, you need to take stock of where you now fall on the learning curve of data literacy.

#big data #latest news #where does your organization fall on the data literacy curve? #organization fall #data literacy curve #fall