CODEWITHSUNDEEP
pythoncmdprogram-entry-pointargparse
DGMS89
DGMS89

Reputation: 1667

Passing directory paths as strings to argparse in Python

Scenario: I have a python script that receives as inputs 2 directory paths (input and output folders) and a variable ID. With these, it performs a data gathering procedure from xlsx and xlsm macros, modifies the data and saves to a csv (from the input folder, the inner functions of the code will run loops, to get multiple files and process them, one at a time).

Issue: Since the code was working fine when I was running it from the Spyder console, I decided to step it up and learn about cmd caller, argparse and the main function. I trying to implement that, but I get the following error:

Unrecognized arguments (the output path I pass from cmd)

Question: Any ideas on what I am doing wrong?

Obs: If the full script is required, I can post it here, but since it works when run from Spyder, I believe the error is in my argparse function.

Code (argparse function and __main__):

# This is a function to parse arguments:
def parserfunc():
    import argparse
    parser = argparse.ArgumentParser(description='Process Files')
    parser.add_argument('strings', nargs=3)
    args = parser.parse_args()
    arguments = args.strings
    return arguments

# This is the main caller    
def main():
    arguments = parserfunc()
    # this next function is where I do the processing for the files, based on the paths and id provided):
    modifierfunc(arguments[0], arguments[1], arguments[2])

#
if __name__ == "__main__":
    main()

Upvotes: 1

Views: 3240

Answers (2)

Paddy
Paddy

Reputation: 123

You could drop the entire parserfunc() function. sys.argv does indeed contain all arguments (always processed as a string) as mentioned by grapes.

So instead of this:

modifierfunc(arguments[0], arguments[1], arguments[2])

This should suffice:

import sys
modifierfunc(sys.argv[0], sys.argv[1], sys.argv[2])

Perhaps, first do a print, to see if the sys.argv holds the values you expect.

print('Argument 0='+sys.argv[0])
print('Argument 1='+sys.argv[1])
print('Argument 2='+sys.argv[2])

Upvotes: 1

grapes
grapes

Reputation: 8636

If you decided to use argparse, then make use of named arguments, not indexed. Following is an example code:

import argparse

parser = argparse.ArgumentParser()
parser.add_argument('input')
parser.add_argument('output')
parser.add_argument('id')

args = parser.parse_args()
print(args.input, args.output, args.id) # this is how you use them

In case you miss one of them on program launch, you will get human readable error message like

error: the following arguments are required: id

Upvotes: 3

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