List of pathlib.Paths Not Ordered As Same List of Same String Filenames

[QbLearningPython]

While testing a module, I have found a weird behaviour of pathlib package. I have a list of pathlib.Paths and I sorted() it. I supposed that the order retrieved by sorted() a list of Paths would be the same as the order retrieved by sorted() a list of their (string) filenames. But it is not the case.

Let me explain.

I have a list of filenames such as :

filenames_for_testing = (
    '/spam/spams.txt',
    '/spam/spam.txt',
    '/spam/another.txt',
    '/spam/binary.bin',
    '/spam/spams/spam.ttt',
    '/spam/spams/spam01.txt',
    '/spam/spams/spam02.txt',
    '/spam/spams/spam03.ppp',
    '/spam/spams/spam04.doc',
)

If I run the following:

sorted_filenames = sorted(filenames_for_testing)
print()
[print(element) for element in sorted_filenames]
print()

the alphabetical (string) order of this list will be:

• /spam/another.txt
  
• /spam/binary.bin
  
• /spam/spam.txt
  
• /spam/spams.txt
  
• /spam/spams/spam.ttt
  
• /spam/spams/spam01.txt
  
• /spam/spams/spam02.txt
  
• /spam/spams/spam03.ppp
  
• /spam/spams/spam04.doc
  

But when I try to order the same list as pathlib.Paths using:

from pathlib import Path

paths_for_testing = [
    Path(filename)
    for filename in filenames_for_testing
]
sorted_paths = sorted(paths_for_testing)

The list returned is (just showing filenames of the pathlib.Paths):

• /spam/another.txt
  
• /spam/binary.bin
  
• /spam/spam.txt
  
• /spam/spams/spam.ttt
  
• /spam/spams/spam01.txt
  
• /spam/spams/spam02.txt
  
• /spam/spams/spam03.ppp
  
• /spam/spams/spam04.doc
  
• /spam/spams.txt
  

which is different from previous list because 'spam/spams.txt' does not go after '/spam/spam.txt' and before all '/spam/spams/*' files (instead, it goes at the end of the list).

You can check it using:

sorted_filenames == [str(path) for path in sorted_paths]

which returns False.

I am not sure this would be a bug. Maybe it is the intended purpose. However, I think that it is a weird behaviour. Unless I am missing something, I can hardly understand why a list of pathlib.Paths and a list with the same string filenames can be ordered in the same fashion.

A crafted script to test this:

from pathlib import Path

# order string filenames

filenames_for_testing = (
    '/spam/spams.txt',
    '/spam/spam.txt',
    '/spam/another.txt',
    '/spam/binary.bin',
    '/spam/spams/spam.ttt',
    '/spam/spams/spam01.txt',
    '/spam/spams/spam02.txt',
    '/spam/spams/spam03.ppp',
    '/spam/spams/spam04.doc',
)

sorted_filenames = sorted(filenames_for_testing)

# output ordered list of string filenames

print()
print("Ordered list of string filenames:")
print()
[print(f'\t{element}') for element in sorted_filenames]
print()

# order paths (build from same string filenames)

paths_for_testing = [
    Path(filename)
    for filename in filenames_for_testing
]
sorted_paths = sorted(paths_for_testing)

# output ordered list of pathlib.Paths

print()
print("Ordered list of pathlib.Paths:")
print()
[print(f'\t{element}'
       ) for element in sorted_paths]
print()

# compare

print()

if sorted_filenames == [str(path) for path in sorted_paths]:
    print('Ordered lists of string filenames and pathlib.Paths are EQUAL.')
    
else:
    print('Ordered lists of string filenames and pathlib.Paths are DIFFERENT.')

    for element in range(0, len(sorted_filenames)):
        
        if sorted_filenames[element] != str(sorted_paths[element]):
            
            print()
            print('First different element:')
            print(f'\tElement #{element}')
            print(f'\t{sorted_filenames[element]} != {sorted_paths[element]}')
            break

print()

I am running Python 3.6.3 on MacOs 10.12.6

Thanks.