How to strip all whitespace from string

Question

Taking advantage of str.split's behavior with no sep parameter:

>>> s = " \t foo \n bar "
>>> "".join(s.split())
'foobar'

If you just want to remove spaces instead of all whitespace:

>>> s.replace(" ", "")
'\tfoo\nbar'

Premature optimization

Even though efficiency isn't the primary goal—writing clear code is—here are some initial timings:

$ python -m timeit '"".join(" \t foo \n bar ".split())'
1000000 loops, best of 3: 1.38 usec per loop
$ python -m timeit -s 'import re' 're.sub(r"\s+", "", " \t foo \n bar ")'
100000 loops, best of 3: 15.6 usec per loop

Note the regex is cached, so it's not as slow as you'd imagine. Compiling it beforehand helps some, but would only matter in practice if you call this many times:

$ python -m timeit -s 'import re; e = re.compile(r"\s+")' 'e.sub("", " \t foo \n bar ")'
100000 loops, best of 3: 7.76 usec per loop

Even though re.sub is 11.3x slower, remember your bottlenecks are assuredly elsewhere. Most programs would not notice the difference between any of these 3 choices.

For Python 3:

>>> import re
>>> re.sub(r'\s+', '', 'strip my \n\t\r ASCII and \u00A0 \u2003 Unicode spaces')
'stripmyASCIIandUnicodespaces'
>>> # Or, depending on the situation:
>>> re.sub(r'(\s|\u180B|\u200B|\u200C|\u200D|\u2060|\uFEFF)+', '', \
... '\uFEFF\t\t\t strip all \u000A kinds of \u200B whitespace \n')
'stripallkindsofwhitespace'

...handles any whitespace characters that you're not thinking of - and believe us, there are plenty.

\s on its own always covers the ASCII whitespace:

• (regular) space
• tab
• new line (\n)
• carriage return (\r)
• form feed
• vertical tab

Additionally:

• for Python 2 with re.UNICODE enabled,
• for Python 3 without any extra actions,

...\s also covers the Unicode whitespace characters, for example:

• non-breaking space,
• em space,
• ideographic space,

...etc. See the full list here, under "Unicode characters with White_Space property".

However \s DOES NOT cover characters not classified as whitespace, which are de facto whitespace, such as among others:

• zero-width joiner,
• Mongolian vowel separator,
• zero-width non-breaking space (a.k.a. byte order mark),

...etc. See the full list here, under "Related Unicode characters without White_Space property".

So these 6 characters are covered by the list in the second regex, \u180B|\u200B|\u200C|\u200D|\u2060|\uFEFF.

Sources:

• https://docs.python.org/2/library/re.html
• https://docs.python.org/3/library/re.html
• https://en.wikipedia.org/wiki/Unicode_character_property

Alternatively,

"strip my spaces".translate( None, string.whitespace )

And here is Python3 version:

"strip my spaces".translate(str.maketrans('', '', string.whitespace))

The simplest is to use replace:

"foo bar\t".replace(" ", "").replace("\t", "")

Alternatively, use a regular expression:

import re
re.sub(r"\s", "", "foo bar\t")

Remove the Starting Spaces in Python

string1 = "    This is Test String to strip leading space"
print(string1)
print(string1.lstrip())

Remove the Trailing or End Spaces in Python

string2 = "This is Test String to strip trailing space     "
print(string2)
print(string2.rstrip())

Remove the whiteSpaces from Beginning and end of the string in Python

string3 = "    This is Test String to strip leading and trailing space      "
print(string3)
print(string3.strip())

Remove all the spaces in python

string4 = "   This is Test String to test all the spaces        "
print(string4)
print(string4.replace(" ", ""))