Echo Bot using Python Telegram Bot

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# This program is dedicated to the public domain under the CC0 license.

"""
Simple Bot to reply to Telegram messages.
First, a few handler functions are defined. Then, those functions are passed to
the Dispatcher and registered at their respective places.
Then, the bot is started and runs until we press Ctrl-C on the command line.
Usage:
Basic Echobot example, repeats messages.
Press Ctrl-C on the command line or send a signal to the process to stop the
bot.
"""

import logging

from telegram.ext import Updater, CommandHandler, MessageHandler, Filters

# Enable logging
logging.basicConfig(format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
                    level=logging.INFO)

logger = logging.getLogger(__name__)


# Define a few command handlers. These usually take the two arguments update and
# context. Error handlers also receive the raised TelegramError object in error.
def start(update, context):
    """Send a message when the command /start is issued."""
    update.message.reply_text('Hi!')


def help(update, context):
    """Send a message when the command /help is issued."""
    update.message.reply_text('Help!')


def echo(update, context):
    """Echo the user message."""
    update.message.reply_text(update.message.text)


def error(update, context):
    """Log Errors caused by Updates."""
    logger.warning('Update "%s" caused error "%s"', update, context.error)


def main():
    """Start the bot."""
    # Create the Updater and pass it your bot's token.
    # Make sure to set use_context=True to use the new context based callbacks
    # Post version 12 this will no longer be necessary
    updater = Updater("TOKEN", use_context=True)

    # Get the dispatcher to register handlers
    dp = updater.dispatcher

    # on different commands - answer in Telegram
    dp.add_handler(CommandHandler("start", start))
    dp.add_handler(CommandHandler("help", help))

    # on noncommand i.e message - echo the message on Telegram
    dp.add_handler(MessageHandler(Filters.text, echo))

    # log all errors
    dp.add_error_handler(error)

    # Start the Bot
    updater.start_polling()

    # Run the bot until you press Ctrl-C or the process receives SIGINT,
    # SIGTERM or SIGABRT. This should be used most of the time, since
    # start_polling() is non-blocking and will stop the bot gracefully.
    updater.idle()


if __name__ == '__main__':
    main()

References
https://github.com/python-telegram-bot/python-telegram-bot/blob/master/examples/echobot2.py

Change Process Priority in Python

def lowpriority():
    """ Set the priority of the process to below-normal."""

    import sys
    try:
        sys.getwindowsversion()
    except AttributeError:
        isWindows = False
    else:
        isWindows = True

    if isWindows:
        # Based on:
        #   "Recipe 496767: Set Process Priority In Windows" on ActiveState
        #   http://code.activestate.com/recipes/496767/
        import win32api,win32process,win32con

        pid = win32api.GetCurrentProcessId()
        handle = win32api.OpenProcess(win32con.PROCESS_ALL_ACCESS, True, pid)
        win32process.SetPriorityClass(handle, win32process.BELOW_NORMAL_PRIORITY_CLASS)
    else:
        import os

        os.nice(1)

References
https://stackoverflow.com/questions/1023038/change-process-priority-in-python-cross-platform

dataframe.groupby in Python Pandas

# importing pandas as pd 
import pandas as pd 

# Creating the dataframe 
df = pd.read_csv("nba.csv") 

# Print the dataframe 
df 
# applying groupby() function to 
# group the data on team value. 
gk = df.groupby('Team') 

# Let's print the first entries 
# in all the groups formed. 
gk.first() 
# Finding the values contained in the "Boston Celtics" group 
gk.get_group('Boston Celtics') 
# importing pandas as pd 
import pandas as pd 

# Creating the dataframe 
df = pd.read_csv("nba.csv") 

# First grouping based on "Team" 
# Within each team we are grouping based on "Position" 
gkk = daf.groupby(['Team', 'Position']) 

# Print the first value in each group 
gkk.first() 

References
https://www.geeksforgeeks.org/python-pandas-dataframe-groupby/

Threading in Python

import logging
import threading
import time

def thread_function(name):
    logging.info("Thread %s: starting", name)
    time.sleep(2)
    logging.info("Thread %s: finishing", name)

if __name__ == "__main__":
    format = "%(asctime)s: %(message)s"
    logging.basicConfig(format=format, level=logging.INFO,
                        datefmt="%H:%M:%S")

    logging.info("Main    : before creating thread")
    x = threading.Thread(target=thread_function, args=(1,))
    logging.info("Main    : before running thread")
    x.start()
    logging.info("Main    : wait for the thread to finish")
    # x.join()
    logging.info("Main    : all done")

Daemon Threads

x = threading.Thread(target=thread_function, args=(1,), daemon=True)

Working With Many Threads

import logging
import threading
import time

def thread_function(name):
    logging.info("Thread %s: starting", name)
    time.sleep(2)
    logging.info("Thread %s: finishing", name)

if __name__ == "__main__":
    format = "%(asctime)s: %(message)s"
    logging.basicConfig(format=format, level=logging.INFO,
                        datefmt="%H:%M:%S")

    threads = list()
    for index in range(3):
        logging.info("Main    : create and start thread %d.", index)
        x = threading.Thread(target=thread_function, args=(index,))
        threads.append(x)
        x.start()

    for index, thread in enumerate(threads):
        logging.info("Main    : before joining thread %d.", index)
        thread.join()
        logging.info("Main    : thread %d done", index)

References
https://realpython.com/intro-to-python-threading/

Draw a rectangle around a region of interest in OpenCV Python

# Python program to explain cv2.rectangle() method 

# importing cv2 
import cv2 

# path 
path = r'C:\Users\Rajnish\Desktop\geeksforgeeks\geeks.png'

# Reading an image in default mode 
image = cv2.imread(path) 

# Window name in which image is displayed 
window_name = 'Image'

# Start coordinate, here (5, 5) 
# represents the top left corner of rectangle 
start_point = (5, 5) 

# Ending coordinate, here (220, 220) 
# represents the bottom right corner of rectangle 
end_point = (220, 220) 

# Blue color in BGR 
color = (255, 0, 0) 

# Line thickness of 2 px 
thickness = 2

# Using cv2.rectangle() method 
# Draw a rectangle with blue line borders of thickness of 2 px 
image = cv2.rectangle(image, start_point, end_point, color, thickness) 

# Displaying the image 
cv2.imshow(window_name, image) 
k = cv2.waitKey(0) # 0==wait forever

References
https://www.geeksforgeeks.org/python-opencv-cv2-rectangle-method/
https://stackoverflow.com/questions/23720875/how-to-draw-a-rectangle-around-a-region-of-interest-in-python