这是最简单的解释。这是我正在使用的:

re.split('\W', 'foo/bar spam\neggs')
>>> ['foo', 'bar', 'spam', 'eggs']

这是我想要的:

someMethod('\W', 'foo/bar spam\neggs')
>>> ['foo', '/', 'bar', ' ', 'spam', '\n', 'eggs']

原因是我想把一个字符串分割成令牌,操作它,然后再把它组合在一起。


当前回答

我发现这种基于生成器的方法更令人满意:

def split_keep(string, sep):
    """Usage:
    >>> list(split_keep("a.b.c.d", "."))
    ['a.', 'b.', 'c.', 'd']
    """
    start = 0
    while True:
        end = string.find(sep, start) + 1
        if end == 0:
            break
        yield string[start:end]
        start = end
    yield string[start:]

它避免了需要找出正确的正则表达式,而在理论上应该相当便宜。它不创建新的字符串对象,并将大部分迭代工作委托给高效的find方法。

... 在Python 3.8中,它可以短到:

def split_keep(string, sep):
    start = 0
    while (end := string.find(sep, start) + 1) > 0:
        yield string[start:end]
        start = end
    yield string[start:]

其他回答

这里有一个简单的.split解决方案,不需要regex。

这是一个没有删除分隔符的Python split()的答案,所以不完全是最初的帖子所要求的,但另一个问题被关闭为这个问题的副本。

def splitkeep(s, delimiter):
    split = s.split(delimiter)
    return [substr + delimiter for substr in split[:-1]] + [split[-1]]

随机测试:

import random

CHARS = [".", "a", "b", "c"]
assert splitkeep("", "X") == [""]  # 0 length test
for delimiter in ('.', '..'):
    for _ in range(100000):
        length = random.randint(1, 50)
        s = "".join(random.choice(CHARS) for _ in range(length))
        assert "".join(splitkeep(s, delimiter)) == s

你也可以用字符串数组而不是正则表达式分割字符串,就像这样:

def tokenizeString(aString, separators):
    #separators is an array of strings that are being used to split the string.
    #sort separators in order of descending length
    separators.sort(key=len)
    listToReturn = []
    i = 0
    while i < len(aString):
        theSeparator = ""
        for current in separators:
            if current == aString[i:i+len(current)]:
                theSeparator = current
        if theSeparator != "":
            listToReturn += [theSeparator]
            i = i + len(theSeparator)
        else:
            if listToReturn == []:
                listToReturn = [""]
            if(listToReturn[-1] in separators):
                listToReturn += [""]
            listToReturn[-1] += aString[i]
            i += 1
    return listToReturn
    

print(tokenizeString(aString = "\"\"\"hi\"\"\" hello + world += (1*2+3/5) '''hi'''", separators = ["'''", '+=', '+', "/", "*", "\\'", '\\"', "-=", "-", " ", '"""', "(", ")"]))

另一个在Python 3上工作良好的非正则表达式解决方案

# Split strings and keep separator
test_strings = ['<Hello>', 'Hi', '<Hi> <Planet>', '<', '']

def split_and_keep(s, sep):
   if not s: return [''] # consistent with string.split()

   # Find replacement character that is not used in string
   # i.e. just use the highest available character plus one
   # Note: This fails if ord(max(s)) = 0x10FFFF (ValueError)
   p=chr(ord(max(s))+1) 

   return s.replace(sep, sep+p).split(p)

for s in test_strings:
   print(split_and_keep(s, '<'))


# If the unicode limit is reached it will fail explicitly
unicode_max_char = chr(1114111)
ridiculous_string = '<Hello>'+unicode_max_char+'<World>'
print(split_and_keep(ridiculous_string, '<'))

一个懒惰而简单的解决方案

假设你的正则表达式模式是split_pattern = r'(!|\?)'

首先,添加一些与新分隔符相同的字符,如'[cut]'

New_string = re.sub(split_pattern, '\\1[cut]', your_string)

然后拆分新的分隔符new_string.split('[cut]')

之前发布的一些答案,会重复分隔符,或者有一些我在自己的情况下遇到的其他错误。你可以使用这个函数:

def split_and_keep_delimiter(input, delimiter):
    result      = list()
    idx         = 0
    while delimiter in input:
        idx     = input.index(delimiter);
        result.append(input[0:idx+len(delimiter)])
        input = input[idx+len(delimiter):]
    result.append(input)
    return result