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Find all installed modules
help("modules");
Virtual Environment

With virtualenv and virtualenvwrapper

# Installing virtualenv and virtualenvwrapper
sudo pip install virtualenv virtualenvwrapper

# Update the profile ~/.bashrc
# Add the  following lines

# Python virtualenv and virtualenvwrapper
export WORKON_HOME=$HOME/.virtualenvs
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
source /usr/local/bin/virtualenvwrapper.sh

# Reload the profile
source ~/.bashrc

# Creating python virtual environment
# The py3cv3 is a self-defined name 
mkvirtualenv py3cv3 -p python3

# Enter the specified virtual environment
workon py3cv3

# Exit the the specified virtual environment
deactivate

# List all of the environments.
lsvirtualenv

# Remove an environment
rmvirtualenv py3cv3
Timestamp
timestamp = datetime.datetime.now()
print("It is {}".format(timestamp.strftime("%A %d %B %Y %I:%M:%S%p")))
Math
total += 1
If-then
# Boolean, none
if motion is not None:
if not flag:

# Number
if delay > 0:
if delay == 0:
if total > frameCount:

# String
if "blue" in style:
if authors.startswith('['):
    authors = authors.lstrip('[').rstrip(']')

# One-liner
def doi_url(d): return f'http://{d}' if d.startswith('doi.org') else f'http://doi.org/{d}'

# Multiple conditions
temperature = 25
if temperature > 30:
    print('Hot')
elif temperature > 20 and temperature <= 30:
    print('Warm')
else:
    print('Cool')
    
# Reverse the True
temperature = 15
if not temperature > 20:
    print('Cool')
#    
temperature = 25
humidity = 55
rain = 0
if temperature > 30 or humidity < 70 and not rain > 0:
    print('Dry conditions')
Command Arguments
import argparse
# construct the argument parser and parse the arguments
ap = argparse.ArgumentParser()
ap.add_argument("-i", "--interval", required=False,
        help="Seconds to Interval (Default:30)", default="30", type=int)
ap.add_argument("-o", "--output", required=False,
        help="Path to Output Logs (Default:std-out)")
args = vars(ap.parse_args())

# Usage
intv = args["interval"]
logfile = args["output"]
#
# Nagios2 HTTP proxy test
#
# usage: check_http_proxy --proxy=proxy:port --auth=user:pass --url=url --timeout=10 --warntime=5 --expect=content

import sys
import getopt

def get_cmdline_cfg():
	try:
		opts, args = getopt.getopt(
			sys.argv[1:],
			"p:a:t:w:e:u:",
			["proxy=", "auth=", "timeout=", "warntime=", "expect=", "url="]
		)
	except getopt.GetoptError, err:
		print("SCRIPT CALLING ERROR: {0}".format(str(err)))

	### Build cfg dictionary
	cfg = {}
	for o, a in opts:
		if o in ("-p", "--proxy"):
			cfg["proxy"] = a
		elif o in ("-a","--auth"):
			cfg["auth"] = a
		elif o in ("-t","--timeout"):
			cfg["timeout"] = float(a)
		elif o in ("-w","--warntime"):
			cfg["warntime"] = float(a)
		elif o in ("-e","--expect"):
			cfg["expect"] = a
		elif o in ("-u","--url"):
			cfg["url"] = a

	# These are required
	for req_param in ("url", "proxy"):
		if req_param not in cfg:
			print("Missing parameter: {0}".format(req_param))

	return cfg
  
# Usage
if __name__ == '__main__':
	cfg = get_cmdline_cfg()
    
	if "auth" in cfg:
		proxy_url = "http://{auth}@{proxy}/".format(**cfg)
	else:
		proxy_url = "http://{proxy}/".format(**cfg)
String
secret_password = 'jhk7GSH8ds'
print('Password hint: the third letter of your password is ' + secret_password[2])
# Escaping characters
introduction = 'Hello, I\'m John!'
print(introduction)

# Joining strings
user_age = 28
user_name = 'John'
greeting = user_name + ', you are ' + str(user_age) + '!'
print(greeting)
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