在python中使用正则表达式捕获表情符号 [英] Capturing emoticons using regular expression in python

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问题描述

我想要一个正则表达式模式来匹配笑脸 ":)" ,":(" .Also 它也应该捕获重复的笑脸,如 ":) :)" , ":) :(" 但过滤掉无效的语法,如":((" .

I would like to have a regex pattern to match smileys ":)" ,":(" .Also it should capture repeated smileys like ":) :)" , ":) :(" but filter out invalid syntax like ":( (" .

我有这个,但它匹配 ":( ("

I have this with me, but it matches ":( ("

bool( re.match("(:\()",str) ) 

我可能在这里遗漏了一些明显的东西,我想为这个看似简单的任务提供一些帮助.

I maybe missing something obvious here, and I'd like some help for this seemingly simple task.

推荐答案

我认为它终于点击"了您在这里问的问题.看看下面的内容:

I think it finally "clicked" exactly what you're asking about here. Take a look at the below:

import re

smiley_pattern = '^(:\(|:\))+$' # matches only the smileys ":)" and ":("

def test_match(s):
    print 'Value: %s; Result: %s' % (
        s,
        'Matches!' if re.match(smiley_pattern, s) else 'Doesn\'t match.'
    )

should_match = [
    ':)',   # Single smile
    ':(',   # Single frown
    ':):)', # Two smiles
    ':(:(', # Two frowns
    ':):(', # Mix of a smile and a frown
]
should_not_match = [
    '',         # Empty string
    ':(foo',    # Extraneous characters appended
    'foo:(',    # Extraneous characters prepended
    ':( :(',    # Space between frowns
    ':( (',     # Extraneous characters and space appended
    ':(('       # Extraneous duplicate of final character appended
]

print('The following should all match:')
for x in should_match: test_match(x);

print('')   # Newline for output clarity

print('The following should all not match:')
for x in should_not_match: test_match(x);

您的原始代码的问题在于您的正则表达式错误:(:\().让我们分解一下.

The problem with your original code is that your regex is wrong: (:\(). Let's break it down.

外面的括号是一个分组".如果您要进行字符串替换,它们就是您要引用的内容,并且用于一次对字符组应用正则表达式运算符.所以,你真的是在说:

The outside parentheses are a "grouping". They're what you'd reference if you were going to do a string replacement, and are used to apply regex operators on groups of characters at once. So, you're really saying:

  • ( 开始一组
    • :\( ...做正则表达式的东西...
    • ( begin a group
      • :\( ... do regex stuff ...

      : 不是正则表达式保留字符,所以它只是一个冒号.\ 是,它的意思是下面的字符是文字​​,不是正则表达式".这称为转义序列".完全解析成英文,你的正则表达式说

      The : isn't a regex reserved character, so it's just a colon. The \ is, and it means "the following character is literal, not a regex operator". This is called an "escape sequence". Fully parsed into English, your regex says

      • ( 开始一组
        • : 一个冒号字符
        • \( 一个左括号字符
        • ( begin a group
          • : a colon character
          • \( a left parenthesis character

          我使用的正则表达式稍微复杂一些,但还不错.让我们分解一下:^(:\(|:\))+$.

          The regex I used is slightly more complex, but not bad. Let's break it down: ^(:\(|:\))+$.

          ^$ 分别表示行首"和行尾".现在我们有...

          ^ and $ mean "the beginning of the line" and "the end of the line" respectively. Now we have ...

          • ^ 行首
            • (:\(|:\))+ ... 做正则表达式 ...
            • ^ beginning of line
              • (:\(|:\))+ ... do regex stuff ...

              ...所以它只匹配构成整行的内容,而不是简单地出现在字符串的中间.

              ... so it only matches things that comprise the entire line, not simply occur in the middle of the string.

              我们知道 () 表示一个分组.+ 表示其中之一".现在我们有:

              We know that ( and ) denote a grouping. + means "one of more of these". Now we have:

              • ^ 行首
              • ( 开始组
                • :\(|:\) ... 做正则表达式 ...
                • ^ beginning of line
                • ( start a group
                  • :\(|:\) ... do regex stuff ...

                  最后是 |(管道)运算符.它的意思是或".因此,应用我们从上文中了解的有关转义字符的知识,我们已准备好完成翻译:

                  Finally, there's the | (pipe) operator. It means "or". So, applying what we know from above about escaping characters, we're ready to complete the translation:

                  • ^ 行首
                  • ( 开始组
                    • : 一个冒号字符
                    • \( 一个左括号字符
                    • ^ beginning of line
                    • ( start a group
                      • : a colon character
                      • \( a left parenthesis character
                      • : 一个冒号字符
                      • \) 一个右括号字符
                      • : a colon character
                      • \) a right parenthesis character

                      我希望这会有所帮助.如果没有,请告诉我,我很乐意通过回复编辑我的答案.

                      I hope this helps. If not, let me know and I'll be happy to edit my answer with a reply.

                      这篇关于在python中使用正则表达式捕获表情符号的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!

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