Winforms: Missing operand after 'Number' operator

I am trying to bind my textbox1 with the datagridview2 so that the textbox can filter the row when the value in textbox and datagridview matches. However, I kept getting the above error. Below is my code

private void textBox1_TextChanged(object sender, EventArgs e)
    {
     (dataGridView2.DataSource as DataTable).DefaultView.RowFilter = string.Format("Vehicle Number LIKE '%{0}%'", textBox1.Text); //error here
     }

#c-sharp #database

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Benjamin Wilkinson

1548767365

There is a space in your column name and thus you will have to escape it. probably like

"[Vehicle Number] LIKE '%{0}%'"

Ray Patel

1619565060

Ternary operator in Python?

Ternary Operator in Python

What is a ternary operator: The ternary operator is a conditional expression that means this is a comparison operator and results come on a true or false condition and it is the shortest way to writing an if-else statement. It is a condition in a single line replacing the multiline if-else code.

syntax : condition ? value_if_true : value_if_false

condition: A boolean expression evaluates true or false

value_if_true: a value to be assigned if the expression is evaluated to true.

value_if_false: A value to be assigned if the expression is evaluated to false.

How to use ternary operator in python here are some examples of Python ternary operator if-else.

Brief description of examples we have to take two variables a and b. The value of a is 10 and b is 20. find the minimum number using a ternary operator with one line of code. ( **min = a if a < b else b ) **. if a less than b then print a otherwise print b and second examples are the same as first and the third example is check number is even or odd.

#python #python ternary operator #ternary operator #ternary operator in if-else #ternary operator in python #ternary operator with dict #ternary operator with lambda

Abdullah Kozey

1617738420

Unformatted input/output operations In C++

In this article, we will discuss the unformatted Input/Output operations In C++. Using objects cin and cout for the input and the output of data of various types is possible because of overloading of operator >> and << to recognize all the basic C++ types. The operator >> is overloaded in the istream class and operator << is overloaded in the ostream class.

The general format for reading data from the keyboard:

cin >> var1 >> var2 >> …. >> var_n;

Here, var1, var2, ……, varn are the variable names that are declared already.
The input data must be separated by white space characters and the data type of user input must be similar to the data types of the variables which are declared in the program.
The operator >> reads the data character by character and assigns it to the indicated location.
Reading of variables terminates when white space occurs or character type occurs that does not match the destination type.

#c++ #c++ programs #c++-operator overloading #cpp-input-output #cpp-operator #cpp-operator-overloading #operators

Ray Patel

1619607900

Perfect Number Program In Python: How to check if a number is perfect or not?

Introduction

A number is said to be the perfect number if the sum of its proper divisors (not including the number itself) is equal to the number.

To get a better idea let’s consider an example, proper divisors of 6 are 1, 2, 3. Now the sum of these divisors is equal to 6 (1+2+3=6), so 6 is said to be a perfect number. Whereas if we consider another number like 12, proper divisors of 12 are 1, 2, 3, 4, 6. Now the sum of these divisors is not equal to 12, so 12 is not a perfect number.

Programming in Python is relatively simpler and more fun when compared to other languages because of its simpler syntax, good readability. Now that we are clear with the concept of perfect number let’s write a python program to check if a number is a perfect number or not. Let’s build a python code for checking if the given user input is a perfect number or not and explore the fun in coding with python.

#data science #how to check if a number is perfect #perfect number #perfect number in python #perfect number program in python #python

Isadore Hermiston

1620418260

Perfect Number Program In Python: How to check if a number is perfect or not?

Introduction

A number is said to be the perfect number if the sum of its proper divisors (not including the number itself) is equal to the number.

To get a better idea let’s consider an example, proper divisors of 6 are 1, 2, 3. Now the sum of these divisors is equal to 6 (1+2+3=6), so 6 is said to be a perfect number. Whereas if we consider another number like 12, proper divisors of 12 are 1, 2, 3, 4, 6. Now the sum of these divisors is not equal to 12, so 12 is not a perfect number.

Programming in Python is relatively simpler and more fun when compared to other languages because of its simpler syntax, good readability. Now that we are clear with the concept of perfect number let’s write a python program to check if a number is a perfect number or not. Let’s build a python code for checking if the given user input is a perfect number or not and explore the fun in coding with python.

#data science #how to check if a number is perfect #perfect number #perfect number in python #perfect number program in python #python

Bongani Ngema

1676389586

PyFCM: Python client for FCM - Firebase Cloud Messaging

PyFCM

Python client for FCM - Firebase Cloud Messaging (Android, iOS and Web)

Firebase Cloud Messaging (FCM) is the new version of GCM. It inherits the reliable and scalable GCM infrastructure, plus new features. GCM users are strongly recommended to upgrade to FCM.

Using FCM, you can notify a client app that new email or other data is available to sync. You can send notifications to drive user reengagement and retention. For use cases such as instant messaging, a message can transfer a payload of up to 4KB to a client app.

Quickstart

Install using pip:

pip install pyfcm

OR

pip install git+https://github.com/olucurious/PyFCM.git

PyFCM supports Android, iOS and Web.

Features

All FCM functionality covered
Tornado support

Examples

Send notifications using the FCMNotification class:

# Send to single device.
from pyfcm import FCMNotification

push_service = FCMNotification(api_key="<api-key>")

# OR initialize with proxies

proxy_dict = {
          "http"  : "http://127.0.0.1",
          "https" : "http://127.0.0.1",
        }
push_service = FCMNotification(api_key="<api-key>", proxy_dict=proxy_dict)

# Your api-key can be gotten from:  https://console.firebase.google.com/project/<project-name>/settings/cloudmessaging

registration_id = "<device registration_id>"
message_title = "Uber update"
message_body = "Hi john, your customized news for today is ready"
result = push_service.notify_single_device(registration_id=registration_id, message_title=message_title, message_body=message_body)

# Send to multiple devices by passing a list of ids.
registration_ids = ["<device registration_id 1>", "<device registration_id 2>", ...]
message_title = "Uber update"
message_body = "Hope you're having fun this weekend, don't forget to check today's news"
result = push_service.notify_multiple_devices(registration_ids=registration_ids, message_title=message_title, message_body=message_body)

print result

Send a data message.

# With FCM, you can send two types of messages to clients:
# 1. Notification messages, sometimes thought of as "display messages."
# 2. Data messages, which are handled by the client app.
# 3. Notification messages with optional data payload.

# Client app is responsible for processing data messages. Data messages have only custom key-value pairs. (Python dict)
# Data messages let developers send up to 4KB of custom key-value pairs.

# Sending a notification with data message payload
data_message = {
    "Nick" : "Mario",
    "body" : "great match!",
    "Room" : "PortugalVSDenmark"
}
# To multiple devices
result = push_service.notify_multiple_devices(registration_ids=registration_ids, message_body=message_body, data_message=data_message)
# To a single device
result = push_service.notify_single_device(registration_id=registration_id, message_body=message_body, data_message=data_message)

# Sending a data message only payload, do NOT include message_body also do NOT include notification body
# To multiple devices
result = push_service.multiple_devices_data_message(registration_ids=registration_ids, data_message=data_message)
# To a single device
result = push_service.single_device_data_message(registration_id=registration_id, data_message=data_message)

# To send extra kwargs (notification keyword arguments not provided in any of the methods),
# pass it as a key value in a dictionary to the method being used
extra_notification_kwargs = {
    'android_channel_id': 2
}
result = push_service.notify_single_device(registration_id=registration_id, data_message=data_message, extra_notification_kwargs=extra_notification_kwargs)

# To process background notifications in iOS 10, set content_available
result = push_service.notify_single_device(registration_id=registration_id, data_message=data_message, content_available=True)

# To support rich notifications on iOS 10, set
extra_kwargs = {
    'mutable_content': True
}





# and then write a NotificationService Extension in your app

# Use notification messages when you want FCM to handle displaying a notification on your app's behalf.
# Use data messages when you just want to process the messages only in your app.
# PyFCM can send a message including both notification and data payloads.
# In such cases, FCM handles displaying the notification payload, and the client app handles the data payload.

Send a low priority message.

# The default is low_priority == False
result = push_service.notify_multiple_devices(registration_ids=registration_ids, message_body=message, low_priority=True)

Get valid registration ids (useful for cleaning up invalid registration ids in your database)

registration_ids = ['reg id 1', 'reg id 2', 'reg id 3', 'reg id 4', ...]
valid_registration_ids = push_service.clean_registration_ids(registration_ids)
# Shoutout to @baali for this

Appengine users should define their environment

push_service = FCMNotification(api_key="<api-key>", proxy_dict=proxy_dict, env='app_engine')
result = push_service.notify_multiple_devices(registration_ids=registration_ids, message_body=message, low_priority=True)

Manage subscriptions to a topic

push_service = FCMNotification(SERVER_KEY)
tokens = [
    <registration_id_1>,
    <registration_id_2>,
]

subscribed = push_service.subscribe_registration_ids_to_topic(tokens, 'test')
# returns True if successful, raises error if unsuccessful

unsubscribed = push_service.unsubscribe_registration_ids_from_topic(tokens, 'test')
# returns True if successful, raises error if unsuccessful

Sending a message to a topic.

# Send a message to devices subscribed to a topic.
result = push_service.notify_topic_subscribers(topic_name="news", message_body=message)

# Conditional topic messaging
topic_condition = "'TopicA' in topics && ('TopicB' in topics || 'TopicC' in topics)"
result = push_service.notify_topic_subscribers(message_body=message, condition=topic_condition)
# FCM first evaluates any conditions in parentheses, and then evaluates the expression from left to right.
# In the above expression, a user subscribed to any single topic does not receive the message. Likewise,
# a user who does not subscribe to TopicA does not receive the message. These combinations do receive it:
# TopicA and TopicB
# TopicA and TopicC
# Conditions for topics support two operators per expression, and parentheses are supported.
# For more information, check: https://firebase.google.com/docs/cloud-messaging/topic-messaging

Other argument options

collapse_key (str, optional): Identifier for a group of messages
    that can be collapsed so that only the last message gets sent
    when delivery can be resumed. Defaults to `None`.
delay_while_idle (bool, optional): If `True` indicates that the
    message should not be sent until the device becomes active.
time_to_live (int, optional): How long (in seconds) the message
    should be kept in FCM storage if the device is offline. The
    maximum time to live supported is 4 weeks. Defaults to ``None``
    which uses the FCM default of 4 weeks.
low_priority (boolean, optional): Whether to send notification with
    the low priority flag. Defaults to `False`.
restricted_package_name (str, optional): Package name of the
    application where the registration IDs must match in order to
    receive the message. Defaults to `None`.
dry_run (bool, optional): If `True` no message will be sent but
    request will be tested.

Get response data.

# Response from PyFCM.
response_dict = {
    'multicast_ids': list(), # List of Unique ID (number) identifying the multicast message.
    'success': 0, #Number of messages that were processed without an error.
    'failure': 0, #Number of messages that could not be processed.
    'canonical_ids': 0, #Number of results that contain a canonical registration token.
    'results': list(), #Array of dict objects representing the status of the messages processed.
    'topic_message_id': None or str
}

# registration_id: Optional string specifying the canonical registration token for the client app that the message
# was processed and sent to. Sender should use this value as the registration token for future requests. Otherwise,
# the messages might be rejected.
# error: String specifying the error that occurred when processing the message for the recipient

For more information, visit: https://firebase.google.com/docs/cloud-messaging/

Links

Project: https://github.com/olucurious/pyfcm
PyPi: https://pypi.python.org/pypi/pyfcm/

Looking for a Django version?

Checkout fcm-django - Link: https://github.com/xtrinch/fcm-django

Updates (Breaking Changes)

MAJOR UPDATES (AUGUST 2017): https://github.com/olucurious/PyFCM/releases/tag/1.4.0

Download Details:

Author: Olucurious
Source Code: https://github.com/olucurious/PyFCM
License: MIT license

#firebase #python #fcm