python: rstrip one exact string, respecting order

问题

Is it possible to use the python command rstrip so that it does only remove one exact string and does not take all letters separately?

I was confused when this happened:

>>>"Boat.txt".rstrip(".txt")
>>>'Boa'

What I expected was:

>>>"Boat.txt".rstrip(".txt")
>>>'Boat'

Can I somehow use rstrip and respect the order, so that I get the second outcome?

回答1:

You're using wrong method. Use str.replace instead:

>>> "Boat.txt".replace(".txt", "")
'Boat'

NOTE: str.replace will replace anywhere in the string.

>>> "Boat.txt.txt".replace(".txt", "")
'Boat'

To remove the last trailing .txt only, you can use regular expression:

>>> import re
>>> re.sub(r"\.txt$", "", "Boat.txt.txt")
'Boat.txt'

If you want filename without extension, os.path.splitext is more appropriate:

>>> os.path.splitext("Boat.txt")
('Boat', '.txt')

回答2:

Define a helper function:

def strip_suffix(s, suf):
    if s.endswith(suf):
        return s[:len(s)-len(suf)]
    return s

or use regex:

import re
suffix = ".txt"
s = re.sub(re.escape(suffix) + '$', '', s)

回答3:

>>> myfile = "file.txt"
>>> t = ""
>>> for i in myfile:
...     if i != ".":
...             t+=i
...     else:
...             break
... 
>>> t
'file'
>>> # Or You can do this
>>> import collections
>>> d = collections.deque("file.txt")
>>> while True:
...     try:
...             if "." in t:
...                     break
...             t+=d.popleft()
...     except IndexError:
...             break
...     finally:
...             filename = t[:-1]
... 
>>> filename
'file'
>>> 

回答4:

This will work regardless of extension type.

# Find the rightmost period character
filename = "my file 1234.txt"

file_extension_position = filename.rindex(".")

# Substring the filename from first char up until the final period position
stripped_filename = filename[0:file_extension_position]
print("Stripped Filename: {}".format(stripped_filename))

来源：https://stackoverflow.com/questions/18723580/python-rstrip-one-exact-string-respecting-order