Python script execution fails with sys.argv on windows

Issue: *.ext is not a valid path

*.ext is not a valid path, but a glob, a kind of pattern to match or find files.

Preferred Solution

Pass the specified files (either as glob-ed expression, or as concrete file-path) directly to a suitable method, that can either expand the path-pattern (glob) or resolve the concrete path.

Pathlib with glob method

Since you already imported and use Pathlib you could use its glob method like this:

from pathlib import Path

paths = list(Path('.').glob('*.txt'))
# [PosixPath('test.txt'), PosixPath('production.txt')]
for path in paths:
    with path.open() as file:
        text = file.read()

The resulting output from comment-line assumes, there are two .txt files in your current directory denoted by ..

Note: You could also pass relative path-expressions to glob like logs/*.txt or even **/*.txt which will math the files in all sub-directories recursively (denoted by **).

What if a user passes a concrete file-path?

Consider, that user might directly pass concrete file-names as arguments. You should test if glob function can deal with it.

If not, you would have to validate for it and select a different path-finder for these cases.

Alternative: Pure globs (jokers, wildcards) in python

Underneath most of these globbing modules (like pathlib) might use Python's pure glob module. This is how it could work here, too:

import glob

filenames = glob.glob('logs/*.txt')
# ['logs/test.txt', 'logs/production.txt']

See also: Using File Extension Wildcards in os.listdir(path)

But as Charlie G adviced introducing another module is not necessary here when Pathlib could do the trick (globbing).

Handle file-name patterns in command-arguments

When passing a file-name pattern like logs/*.txt via the command-line, you should treat each argument separately.

For example a program call from console/shell like:

python script_name.py logs/*.txt 

would work like this:

from pathlib import Path

if __name__ == "__main__":
    # the first element (with index 0) is the program called
    path_patterns = sys.argv[1:]  # get all arguments as list by slicing
    print('got arguments:', path_expressions)

    for pattern in path_patterns:
        paths = Path.cwd().glob(pattern)
        print('file-pattern: ', pattern, 'globbed to paths: ', paths)

Note: it is important that glob method requires a single pattern as string ( type str), not a list. If you pass a list to the method like glob(path_patterns) you will get an error like:

TypeError: expected str, bytes or os.PathLike object, not list

Your sys.argv[1:] uses slicing to get all arguments passed on the command-line. So the resulting list could contain 0, 1 or multiple elements.

Validate command line arguments

If you only require 1 single argument (the "globbed" file-path) then use path_pattern = sys.argv[1].

Furthermore it would be good style and defensive programming to check for the number of arguments before (to avoid an out-of-bounds exception).

This could be done like this:

# guard-statement testing for required number of arguments (program + 1 = 2)
if len(sys.argv) < 2:
    print('Requires at least a single argument, the file-path!')
    print('Usage: python script_name.py <file-path>')
    print('Example: python script_name.py logs/*.txt')
    sys.exit()

# continue because here you are sure at least 1 argument exists
print('got at least 1 required argument: ', sys.argv[1:])

See also:

• How to read/process command line arguments?
• passing variable number of required and optional arguments through command line