How do I access command line arguments in Python

Question

I use python to create my project settings setup  but I need help getting the command line arguments   I tried this on the terminal    python myfile py var1 var2 var3   In my Python file  I want to use all variables that are input

User · Answer

If you call it like this    python myfile py var1 var2 var3  import sys  var1   sys argv 1  var2   sys argv 2  var3   sys argv 3    Similar to arrays you also have sys argv 0  which is always the current working directory

User · Answer

I highly recommend argparse which comes with Python 2 7 and later    The argparse module reduces boiler plate code and makes your code more robust  because the module handles all standard use cases  including subcommands   generates the help and usage for you  checks and sanitize the user input - all stuff you have to worry about when you are using sys argv approach  And it is for free  built-in    Here a small example   import argparse  parser   argparse ArgumentParser  simple example   parser add argument  counter   help  An integer will be increased by 1 and printed    type int  args   parser parse args   print args counter   1    and the output for python prog py -h  usage  simple example  -h  counter  positional arguments    counter     counter will be increased by 1 and printed   optional arguments    -h  --help  show this help message and exit   and for python prog py 1 as you would expect   2

User · Answer

Python code   import sys    main param 1  sys argv 1   param 2  sys argv 2   param 3  sys argv 3    print  Params    param 1  param 2  param 3   Invocation    python myfile py var1 var2 var3   Output   Params  var1 var2 var3

User · Answer

Some additional things that I can think of    As  allsyed said sys argv gives a list of components  including program name   so if you want to know the number of elements passed through command line you can use len   to determine it  Based on this  you can design exception error messages if user didn t pass specific number of parameters   Also if you looking for a better way to handle command line arguments  I would suggest you look at https   docs python org 2 howto argparse html

User · Answer

You can use sys argv to get the arguments as a list   If you need to access individual elements  you can use  sys argv i      where i is index  0 will give you the python filename being executed  Any index after that are the arguments passed

User · Answer

import sys  sys argv 1     will give you a list of arguments  not including the name of the python file

User · Answer

Python tutorial explains it   import sys  print sys argv    More specifically  if you run python example py one two three    gt  gt  gt  import sys  gt  gt  gt  print sys argv    example py    one    two    three

User · Answer

First  You will need to import sys  sys - System-specific parameters and functions  This module provides access to certain variables used and maintained by the interpreter  and to functions that interact strongly with the interpreter  This module is still available  I will edit this post in case this module is not working anymore  And then  you can print the numbers of arguments or what you want here  the list of arguments  Follow the script below      usr bin python  import sys  print  Number of arguments entered    len sys argv   print  Your argument list    str sys argv   Then  run your python script     python arguments List py chocolate milk hot Chocolate  And you will have the result that you were asking   Number of arguments entered   4 Your argument list     arguments List py    chocolate    milk    hot Chocolate    Hope that helped someone

[python] How do I access command line arguments in Python?

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