CODEWITHSUNDEEP
python
InquilineKea
InquilineKea

Reputation: 891

How do I get a Python program to take in parameters as inputs that come from standard input from the UNIX terminal?

For example - I want to do something like...

python DoublePendulum.py INPUT1 INPUT2

(where INPUT1 and INPUT2 are taken as variable inputs within the DoublePendulum program).

Upvotes: 0

Views: 106

Answers (2)

Jose Maria
Jose Maria

Reputation: 63

$ python test.py one two five something

inside test.py

import sys
print(sys.argv[0:1], sys.argv[1:2], sys.argv[2:3], sys.argv[3:4], sys.argv[4:5])

will output as lists:

['test.py'] ['one'] ['two'] ['five'] ['something']

for my_var in sys.argv:
    print(my_var)

will output: as strings

test.py  
one  
two  
five  
something

I made this function for that returns the parameter you want

def give_me_arg(n):
    num = len(sys.argv)
    if n >= num:
        print("Only enter:>",num,'<-and are this from 0 to ',num-1,':', sys.argv)
        return ''
    else:
        for my_var in sys.argv[n:n+1]:
            return my_var

my_var=give_me_arg(3)

Upvotes: 1

avasal
avasal

Reputation: 14872

$ python test.py arg1 arg2 arg3

In test.py 

import sys

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

output

Number of arguments: 4 arguments.
Argument List: ['test.py', 'arg1', 'arg2', 'arg3']

Python also provided modules that helps you parse command-line options and arguments. There are the following modules in the standard library:

  • The getopt module is similar to GNU getopt.
  • The optparse module offers object-oriented command line option parsing, optparse was deprecated in version 2.7 of Python argparse is the replacement.

Upvotes: 5

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