How to pass an array to python through command line [duplicate]

Answer 1

Commandline arguments are strings. Even integers have to be converted from string to int. If you use the list syntax you show in your example, you'll need to run the argument through some sort of parser (your own parser, something from ast, or eval-- but don't use eval). But there's a simpler way: Just write the arguments separately, and use a slice of sys.argv as your list. Space-separated arguments is the standard way to pass multiple arguments to a commandline program (e.g., multiple filenames to less, rm, etc.).

python3 test.py -n a b c 1 2 3

First you'd identify and skip arguments that have a different purpose (-n in the above example), then simply keep the rest:

arr = sys.argv[2:]
print(arr[3])   # Prints "1"

PS. You also need to protect any argument from the shell, by quoting any characters with special meaning(*, ;, spaces that are part of an argument, etc.). But that's a separate issue.

Answer 2

The elements of argv are strings, they're not parsed like literals in the program.

You should just pass a comma-separated string (without the brackets):

python3 test.py 1,2,3,4,5 0

and then use split() to convert it to an array.

import sys
arr = sys.argv[1].split(',')
print(arr[2])