如何在PHP中使用正则表达式获取每个单词的首字母 [英] How to get first letter of every word using regex in PHP

问题描述

我有一个字符串变量，我想获取它的每个单词的第一个字母.我希望最终结果是第一个字母的数组.

I have a string variable and I want to get the first letter of every word of it. I want the end result to be an array of first letters.

$language = 'Sample Language';
preg_match('/(\b[a-z])+/i', $language, $match);
print_r($match);

我得到的只是第一个单词的第一个字母.上面打印 Array([0]=>S [1]=>S)

What I am getting is only the first letter of the first word. The above prints Array([0]=>S [1]=>S)

如果我改成

preg_match('/(\bL)+/i', $language, $match);

我可以匹配第二个单词的 L.所以很明显，在第一场比赛之后，它停止寻找其余的比赛.我不太擅长正则表达式.谁能指出我做错了什么?

I can get a match for the L of the second word. So obviously after the first match it stops looking for the rest. I am not very good with regular expressions. Can anyone point out what I have done wrong?

输入字符串中的单词并不总是用空格分隔.这是相当不可预测的.我遇到的一些格式:主要语言:语言"主要语言，语言"MainLanguage:Language-SubLanguage"这里我想得到M，L和S

words in input string are not always separated by space. It is quite unpredictable. Some formats I have come across: "MainLanguage: Language" "MainLanguage, Language" "MainLanguage: Language-SubLanguage" here I want to get M, L and S

推荐答案

首先使用 preg_match_all 来解决这个问题，其次你不需要 + 量词:

First of all use preg_match_all for this, and secondly you don't need the + quantifier:

$language = 'Sample Language';
preg_match_all('/\b\w/', $language, $match);
print_r($match);

• \b:匹配一个词边界，词边界是一个词字符与一个非词字符分开的位置.单词字符通常是[a-zA-Z0-9_].
• \w:匹配一个单词字符.
• \b\w 匹配位于单词边界位置的单词字符，在这种情况下，紧跟在分隔单词的空格或字符串开头之后.
• \b: Matches a word boundary, a word boundary is a position that separates a word character from a non-word character. Word characters are usually [a-zA-Z0-9_].
• \w: Matches a word character.
• \b\w Matches a word character that is at a word boundary position, in this case right after the space or the start-of-string that separates the words.

如果你想要驼峰式情况，那么你可以将前面的表达式与另一个这样的表达式结合起来:

In case you want camel case situations then you can combine the previous expression with another one like this:

\b\w|(?<=\p{Ll})\p{Lu}

表达式的第二部分，即 (?<=\w)\p{Lu} 应该匹配任何单词字符，如果它是大写字符 \p{Lu} 后面的小写字母 \p{Ll} 应该涵盖驼峰情况，原始表达式涵盖使用连字符 - 分隔的情况两个字.

The second part of the expression, namely (?<=\w)\p{Lu} should match any word character if it is an uppercase character \p{Lu} following a lowercase one \p{Ll} which should cover the camel case situation, the original expressions covers the situation when a hyphen - is used to separate the two words.

Regex101 演示

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