python: rstrip one exact string, respecting order

Question

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?

Asked By: aldorado

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Source

Answer 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')

Answered By: falsetru

Answer 2

Starting with Python 3.9, use .removesuffix():

"Boat.txt".removesuffix(".txt")

On earlier versions of Python, you’ll have to either define it yourself:

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

(you need to check that suf isn’t empty, otherwise removing an empty suffix e.g. removesuffix("boat", "") will do return s[:0] and return "" instead of "boat")

or use regex:

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

Answered By: nneonneo

Answer 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'
>>>

Answered By: Th3carpenter

Answer 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))

Answered By: chris peckham

Answer 5

In Python 3.9, as part of PEP-616, you can now use the removeprefix and removesuffix functions:

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

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

Answered By: nneonneo

Answer 6

In addition to the other excellent answers, sometimes rpartiton may also get you there (depends on the exact usecase).

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

>> "Boat.txt".rpartition('.txt')[0]
'Boat'

Answered By: Xaser

Answer 7

>>> foo="Boat.txt"
>>> foo[:foo.rfind(".txt")]
'Boat'

Answered By: Stanley Yang

python: rstrip one exact string, respecting order

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