Command line input in Python

It is not at all clear what the OP meant (even after some back-and-forth in the comments), but here are two answers to possible interpretations of the question:

For interactive user input (or piped commands or redirected input)

Use raw_input in Python 2.x, and input in Python 3. (These are built in, so you don't need to import anything to use them; you just have to use the right one for your version of python.)

For example:

user_input = raw_input("Some input please: ")

More details can be found here.

So, for example, you might have a script that looks like this

# First, do some work, to show -- as requested -- that# the user input doesn't need to come first.from __future__ import print_functionvar1 = 'tok'var2 = 'tik'+var1print(var1, var2)# Now ask for inputuser_input = raw_input("Some input please: ") # or `input("Some...` in python 3# Now do something with the aboveprint(user_input)

If you saved this in foo.py, you could just call the script from the command line, it would print out tok tiktok, then ask you for input. You could enter bar baz (followed by the enter key) and it would print bar baz. Here's what that would look like:

$ python foo.pytok tiktokSome input please: bar bazbar baz

Here, $ represents the command-line prompt (so you don't actually type that), and I hit Enter after typing bar baz when it asked for input.

For command-line arguments

Suppose you have a script named foo.py and want to call it with arguments bar and baz from the command line like

$ foo.py bar baz

(Again, $ represents the command-line prompt.) Then, you can do that with the following in your script:

import sysarg1 = sys.argv[1]arg2 = sys.argv[2]

Here, the variable arg1 will contain the string 'bar', and arg2 will contain 'baz'. The object sys.argv is just a list containing everything from the command line. Note that sys.argv[0] is the name of the script. And if, for example, you just want a single list of all the arguments, you would use sys.argv[1:].

Just Taking Input

the_input = raw_input("Enter input: ")

And that's it.

Moreover, if you want to make a list of inputs, you can do something like:

a = []for x in xrange(1,10):    a.append(raw_input("Enter Data: "))

In that case, you'll be asked for data 10 times to store 9 items in a list.

Output:

Enter data: 2Enter data: 3Enter data: 4Enter data: 5Enter data: 7Enter data: 3Enter data: 8Enter data: 22Enter data: 5>>> a['2', '3', '4', '5', '7', '3', '8', '22', '5']

You can search that list the fundamental way with something like (after making that list):

if '2' in a:    print "Found"

else: print "Not found."

You can replace '2' with "raw_input()" like this:

if raw_input("Search for: ") in a:    print "Found"else:     print "Not found"

Taking Raw Data From Input File via Commandline Interface

If you want to take the input from a file you feed through commandline (which is normally what you need when doing code problems for competitions, like Google Code Jam or the ACM/IBM ICPC):

example.py

while(True):    line = raw_input()    print "input data: %s" % line

In command line interface:

example.py < input.txt

Hope that helps.

If you're using Python 3, raw_input has changed to input

Python 3 example:

line = input('Enter a sentence:')