如何在Python中删除字符串的前导和尾随空白?

因此，下面的解决方案将删除开头和结尾空白以及中间空白。比如，如果你需要得到一个没有多个空格的清晰字符串值。

>>> str_1 = '     Hello World'
>>> print(' '.join(str_1.split()))
Hello World
>>>
>>>
>>> str_2 = '     Hello      World'
>>> print(' '.join(str_2.split()))
Hello World
>>>
>>>
>>> str_3 = 'Hello World     '
>>> print(' '.join(str_3.split()))
Hello World
>>>
>>>
>>> str_4 = 'Hello      World     '
>>> print(' '.join(str_4.split()))
Hello World
>>>
>>>
>>> str_5 = '     Hello World     '
>>> print(' '.join(str_5.split()))
Hello World
>>>
>>>
>>> str_6 = '     Hello      World     '
>>> print(' '.join(str_6.split()))
Hello World
>>>
>>>
>>> str_7 = 'Hello World'
>>> print(' '.join(str_7.split()))
Hello World

正如你所看到的，这将删除字符串中所有的空格(所有输出都是Hello World)。地点并不重要。但如果确实需要前导和尾随空格，则可以找到strip()。

这将删除myString中所有前导和尾部的空格:

myString.strip()

这也可以用正则表达式来实现

import re

input  = " Hello "
output = re.sub(r'^\s+|\s+$', '', input)
# output = 'Hello'

我想删除字符串中过多的空格(也在字符串之间，而不仅仅是在开头或结尾)。我做了这个，因为我不知道该怎么做:

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)

这将取代一个空间中的双精度空间，直到不再有双精度空间

我无法找到我正在寻找的解决方案，所以我创建了一些自定义函数。你可以试试。

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)))

要移除字符串周围的所有空白，请使用.strip()。例子:

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

注意str.strip()删除所有空白字符，包括制表符和换行符。若要仅删除空格，请指定要删除的特定字符作为strip的参数:

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

最多只删除一个空格:

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

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