剥离字符串并获取开始索引和结束索引 [英] Stripping a string and getting start index and end index

问题描述

Python 中是否有任何直接的方法来剥离字符串并获取开始索引和结束索引?

示例:给定字符串 ' hello world!'，我想要被剥离的字符串 'hello world!' 以及起始索引 2 和索引 14.

' 世界你好！'.strip() 只返回剥离后的字符串.

我可以写一个函数:

def strip(str):'''取一个字符串作为输入.返回剥离的字符串以及开始索引和结束索引.示例:'你好世界！' -->('你好世界！', 2, 14)该函数的计算效率不高，因为它对字符串执行多次传递.'''str_stripped = str.strip()index_start = str.find(str_stripped)index_end = index_start + len(str_stripped)返回 str_stripped、index_start、index_end定义主():str = '你好世界！'str_stripped, index_start, index_end = strip(str)打印('index_start: {0}\tindex_end: {1}'.format(index_start, index_end))如果 __name__ == "__main__":主要的()

但我想知道 Python 或一个流行的库是否提供了任何内置的方法来做到这一点.

解决方案

一种选择(可能不是最直接的)是使用正则表达式:

<预><代码>>>>进口重新>>>s = '你好世界！'>>>match = re.search(r"^\s*(\S.*?)\s*$", s)>>>match.group(1)、match.start(1)、match.end(1)('你好世界！', 2, 14)

^\s*(\S.*?)\s*$ 模式中的位置:

• ^ 是一个字符串的开头
• \s* 零个或多个空格字符
• (\S.*?) 是一个捕获组，它将捕获一个非空格字符，后跟任意字符在 非贪婪时尚
• $ 是一个字符串的结尾

Is there any straightforward way in Python to strip a string and get the start index and the end index?

Example: Given the string ' hello world! ', I want to the stripped string 'hello world!' As well as the start index 2 and the and index 14.

' hello world! '.strip() only returns the stripped string.

I could write a function:

def strip(str):
    '''
    Take a string as input.
    Return the stripped string as well as the start index and end index.
    Example: '  hello world!   '  --> ('hello world!', 2, 14)
    The function isn't computationally efficient as it does more than one pass on the string.
    '''
    str_stripped = str.strip()
    index_start = str.find(str_stripped)
    index_end = index_start + len(str_stripped)
    return str_stripped, index_start, index_end

def main():
    str = '  hello world!   '
    str_stripped, index_start, index_end = strip(str)
    print('index_start: {0}\tindex_end: {1}'.format(index_start, index_end))

if __name__ == "__main__":
    main()

but I wonder whether Python or one popular library provides any built-in way to do so.

解决方案

One option (probably not the most straight-forward) would be to do it with regular expressions:

>>> import re
>>> s = '  hello world!   '
>>> match = re.search(r"^\s*(\S.*?)\s*$", s)
>>> match.group(1), match.start(1), match.end(1)
('hello world!', 2, 14)

where in ^\s*(\S.*?)\s*$ pattern:

• ^ is a beginning of a string
• \s* zero or more space characters
• (\S.*?) is a capturing group that would capture a non-space character followed by any characters any number of times in a non-greedy fashion
• $ is an end of a string

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