python arguments example

Example 1: python read arguments

#!/usr/bin/python

import sys

print('Number of arguments:', len(sys.argv), 'arguments.')
print('Argument List:', str(sys.argv))

Example 2: python arguments

import sys

print ("the script has the name %s" % (sys.argv[0])

Example 3: python function arguments

#*args and **kwargs are normally used as arguments when calling the function.

#*args returns as tuple and **kwargs returns as dictionary.

#*args and **kwargs  let you write functions with variable number of arguments in python.

def func(required,*args,**kwargs):
    return f"{required} {args} {kwargs}"
  
func("Nagendra",5,32,2,1,23,) #output == 'Nagendra (5, 32, 2, 1, 23) {}'
func("Nagendra",5,32,2,1,23,key1="55",key2="75") #output == "Nagendra (5, 32, 2, 1, 23) {'key1': '55', 'key2': '75'}"

#Very understable example of args.
#Given n number of arguments in a function calculate its average
def average(*args):
  '''
  As we already know *args means collection of values in a tuple.
  INPUT: arguments are given. example average(4,10,) 
  OUTPUT: average of two numbers (4+10)/2 == 14
  '''
  return sum(args)/len(args)

average(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15) #output == 8.0

Example 4: python main args

#!/usr/bin/python

import sys, getopt

def main(argv):
   inputfile = ''
   outputfile = ''
   try:
      opts, args = getopt.getopt(argv,"hi:o:",["ifile=","ofile="])
   except getopt.GetoptError:
      print 'test.py -i <inputfile> -o <outputfile>'
      sys.exit(2)
   for opt, arg in opts:
      if opt == '-h':
         print 'test.py -i <inputfile> -o <outputfile>'
         sys.exit()
      elif opt in ("-i", "--ifile"):
         inputfile = arg
      elif opt in ("-o", "--ofile"):
         outputfile = arg
   print 'Input file is "', inputfile
   print 'Output file is "', outputfile

if __name__ == "__main__":
   main(sys.argv[1:])