仅检测正则表达式中的数字 [英] Detection of only the number in regex

问题描述

我有以下正则表达式:

(?<!__num)10\b

当我想从下面的句子中检测 10 时

and when I want to detect 10 from the following sentence

这句话能不能有B110\数字和10个数字

can there be B110\ numbers and 10 numbers in this sentence

返回以下内容

这句话中能不能有B110\数字和10数字

can there be B110\ numbers and 10 numbers in this sentence

但是我不想在110里面检测到10，所以我把正则表达式改成了

but I do not want 10 to be detected inside 110, so I changed the regex to

[^\d+](?<!__num)10\b

在这种情况下，返回的结果前有一个空格字符 10.

In that case, the result returned with 10 preceding a space character.

我只想识别正则表达式中给出的数字.例如，如果我在正则表达式中用 110 代替 10，即使前面有B"，我也希望识别 110.那么我该如何构建正则表达式呢?谢谢.

I want only the number given in the regex to be identified. For example, If I give 110 in place of 10 in the regex, I want 110 to be identified even if preceded by "B." So how can I construct the regex? Thank you.

推荐答案

您可以使用

(?<!__num)(?<!\d)10(?!\d)

查看正则表达式演示

前两个负向后视将在字符串中的相同位置执行，并且 (?<!__num) 将确保在紧接之前没有 __num当前位置和 (? 将确保没有数字.

The first two negative lookbehinds will be executed at the same location in a string and (?<!__num) will make sure there is no __num immediately before the current location and (?<!\d) will make sure there is no digit.

(?!\d) 负前瞻将确保当前位置之后(给定数字之后)没有数字.

The (?!\d) negative lookahead will make sure there is no digit immediately after the current location (after a given number).

Python 演示:

import re
# val = "110" # => <_sre.SRE_Match object; span=(14, 17), match='110'>
val = "10"
s = "can there be B110 numbers and 10 numbers in this sentence"
print(re.search(r'(?<!__num)(?<!\d){}(?!\d)'.format(val), s))
# => <_sre.SRE_Match object; span=(30, 32), match='10'>

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