How do I trim whitespace from a string?

Question

How do I remove leading and trailing whitespace from a string in Python?

For example:

" Hello " --> "Hello"
" Hello"  --> "Hello"
"Hello "  --> "Hello"
"Bob has a cat" --> "Bob has a cat"

Answer 1

Just one space, or all such spaces? If the second, then strings already have a .strip() method:

>>> ' Hello '.strip()
'Hello'
>>> ' Hello'.strip()
'Hello'
>>> 'Bob has a cat'.strip()
'Bob has a cat'
>>> '          Hello        '.strip()  # ALL spaces at ends removed
'Hello'

If you need only to remove one space however, you could do it with:

def strip_one_space(s):
    if s.endswith(" "): s = s[:-1]
    if s.startswith(" "): s = s[1:]
    return s

>>> strip_one_space("   Hello ")
'  Hello'

Also, note that str.strip() removes other whitespace characters as well (e.g. tabs and newlines). To remove only spaces, you can specify the character to remove as an argument to strip, i.e.:

>>> "  Hello\n".strip(" ")
'Hello\n'

Answer 2

As pointed out in answers above

myString.strip()

will remove all the leading and trailing whitespace characters such as \n, \r, \t, \f, space.

For more flexibility use the following

• Removes only leading whitespace chars: myString.lstrip()
• Removes only trailing whitespace chars: myString.rstrip()
• Removes specific whitespace chars: myString.strip('\n') or myString.lstrip('\n\r') or myString.rstrip('\n\t') and so on.

More details are available in the docs

Answer 3

strip is not limited to whitespace characters either:

# remove all leading/trailing commas, periods and hyphens
title = title.strip(',.-')

Answer 4

This will remove all leading and trailing whitespace in myString:

myString.strip()

Answer 5

You want strip():

myphrases = [ " Hello ", " Hello", "Hello ", "Bob has a cat" ]

for phrase in myphrases:
    print phrase.strip()

Answer 6

I wanted to remove the too-much spaces in a string (also in between the string, not only in the beginning or end). I made this, because I don't know how to do it otherwise:

string = "Name : David         Account: 1234             Another thing: something  " 

ready = False
while ready == False:
    pos = string.find("  ")
    if pos != -1:
       string = string.replace("  "," ")
    else:
       ready = True
print(string)

This replaces double spaces in one space until you have no double spaces any more

Answer 7

I could not find a solution to what I was looking for so I created some custom functions. You can try them out.

def cleansed(s: str):
    """:param s: String to be cleansed"""
    assert s is not (None or "")
    # return trimmed(s.replace('"', '').replace("'", ""))
    return trimmed(s)


def trimmed(s: str):
    """:param s: String to be cleansed"""
    assert s is not (None or "")
    ss = trim_start_and_end(s).replace('  ', ' ')
    while '  ' in ss:
        ss = ss.replace('  ', ' ')
    return ss


def trim_start_and_end(s: str):
    """:param s: String to be cleansed"""
    assert s is not (None or "")
    return trim_start(trim_end(s))


def trim_start(s: str):
    """:param s: String to be cleansed"""
    assert s is not (None or "")
    chars = []
    for c in s:
        if c is not ' ' or len(chars) > 0:
            chars.append(c)
    return "".join(chars).lower()


def trim_end(s: str):
    """:param s: String to be cleansed"""
    assert s is not (None or "")
    chars = []
    for c in reversed(s):
        if c is not ' ' or len(chars) > 0:
            chars.append(c)
    return "".join(reversed(chars)).lower()


s1 = '  b Beer '
s2 = 'Beer  b    '
s3 = '      Beer  b    '
s4 = '  bread butter    Beer  b    '

cdd = trim_start(s1)
cddd = trim_end(s2)
clean1 = cleansed(s3)
clean2 = cleansed(s4)

print("\nStr: {0} Len: {1} Cleansed: {2} Len: {3}".format(s1, len(s1), cdd, len(cdd)))
print("\nStr: {0} Len: {1} Cleansed: {2} Len: {3}".format(s2, len(s2), cddd, len(cddd)))
print("\nStr: {0} Len: {1} Cleansed: {2} Len: {3}".format(s3, len(s3), clean1, len(clean1)))
print("\nStr: {0} Len: {1} Cleansed: {2} Len: {3}".format(s4, len(s4), clean2, len(clean2)))