PHP：提取括号内文本的最佳方法？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/196520/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
PHP: Best way to extract text within parenthesis?
提问by Wilco
What's the best/most efficient way to extract text set between parenthesis? Say I wanted to get the string "text" from the string "ignore everything except this (text)" in the most efficient manner possible.
在括号之间提取文本集的最佳/最有效方法是什么？假设我想以最有效的方式从字符串“忽略除此（文本）之外的所有内容”中获取字符串“文本”。
So far, the best I've come up with is this:
到目前为止，我想出的最好的是：
$fullString = "ignore everything except this (text)";
$start = strpos('(', $fullString);
$end = strlen($fullString) - strpos(')', $fullString);
$shortString = substr($fullString, $start, $end);
Is there a better way to do this? I know in general using regex tends to be less efficient, but unless I can reduce the number of function calls, perhaps this would be the best approach? Thoughts?
有一个更好的方法吗？我知道通常使用正则表达式效率较低，但除非我可以减少函数调用的数量，否则这可能是最好的方法？想法？
回答by Owen
i'd just do a regex and get it over with. unless you are doing enough iterations that it becomes a huge performance issue, it's just easier to code (and understand when you look back on it)
我只是做一个正则表达式并完成它。除非您进行了足够多的迭代，否则它会成为一个巨大的性能问题，否则编码会更容易（并在您回顾时理解）
$text = 'ignore everything except this (text)';
preg_match('#\((.*?)\)#', $text, $match);
print $match[1];
回答by Edward Z. Yang
So, actually, the code you posted doesn't work: substr()'sparameters are $string, $start and $length, and strpos()'sparameters are $haystack, $needle. Slightly modified:
因此，实际上，您发布的代码不起作用：substr()'s参数是 $string、$start 和$length，strpos()'s参数是$haystack, $needle。稍作修改：
$str = "ignore everything except this (text)";
$start = strpos($str, '(');
$end = strpos($str, ')', $start + 1);
$length = $end - $start;
$result = substr($str, $start + 1, $length - 1);
Some subtleties: I used $start + 1in the offset parameter in order to help PHP out while doing the strpos()search on the second parenthesis; we increment $startone and reduce $lengthto exclude the parentheses from the match.
一些微妙之处：我$start + 1在 offset 参数中使用，以便在strpos()搜索第二个括号时帮助 PHP ；我们增加一并$start减少$length以从匹配中排除括号。
Also, there's no error checking in this code: you'll want to make sure $startand $enddo not === false before performing the substr.
此外，还有没有错误在此代码检查：你要确保$start和$end不===假执行前substr。
As for using strpos/substrversus regex; performance-wise, this code will beat a regular expression hands down. It's a little wordier though. I eat and breathe strpos/substr, so I don't mind this too much, but someone else may prefer the compactness of a regex.
至于使用strpos/substr与正则表达式；在性能方面，此代码将击败正则表达式。不过有点啰嗦。我吃和呼吸strpos/substr，所以我不太介意这一点，但其他人可能更喜欢正则表达式的紧凑性。
回答by Rob
Use a regular expression:
使用正则表达式：
if( preg_match( '!\(([^\)]+)\)!', $text, $match ) )
$text = $match[1];
回答by Sachin Murali G
This is a sample code to extract all the text between '[' and ']' and store it 2 separate arrays(ie text inside parentheses in one array and text outside parentheses in another array)
这是一个示例代码，用于提取 '[' 和 ']' 之间的所有文本并将其存储在 2 个单独的数组中（即一个数组中括号内的文本和另一个数组中括号外的文本）
function extract_text($string)
{
$text_outside=array();
$text_inside=array();
$t="";
for($i=0;$i<strlen($string);$i++)
{
if($string[$i]=='[')
{
$text_outside[]=$t;
$t="";
$t1="";
$i++;
while($string[$i]!=']')
{
$t1.=$string[$i];
$i++;
}
$text_inside[] = $t1;
}
else {
if($string[$i]!=']')
$t.=$string[$i];
else {
continue;
}
}
}
if($t!="")
$text_outside[]=$t;
var_dump($text_outside);
echo "\n\n";
var_dump($text_inside);
}
Output: extract_text("hello how are you?"); will produce:
输出：extract_text("你好，你好吗？"); 将产生：
array(1) {
[0]=>
string(18) "hello how are you?"
}
array(0) {
}
extract_text("hello [http://www.google.com/test.mp3] how are you?"); will produce
extract_text("你好 [http://www.google.com/test.mp3] 你好吗？"); 会产生
array(2) {
[0]=>
string(6) "hello "
[1]=>
string(13) " how are you?"
}
array(1) {
[0]=>
string(30) "http://www.google.com/test.mp3"
}
回答by vijay
This function may be useful.
这个功能可能有用。
public static function getStringBetween($str,$from,$to, $withFromAndTo = false)
{
$sub = substr($str, strpos($str,$from)+strlen($from),strlen($str));
if ($withFromAndTo)
return $from . substr($sub,0, strrpos($sub,$to)) . $to;
else
return substr($sub,0, strrpos($sub,$to));
}
$inputString = "ignore everything except this (text)";
$outputString = getStringBetween($inputString, '(', ')'));
echo $outputString;
//output will be test
$outputString = getStringBetween($inputString, '(', ')', true));
echo $outputString;
//output will be (test)
strpos() => which is used to find the position of first occurance in a string.
strpos() => 用于查找字符串中第一次出现的位置。
strrpos() => which is used to find the position of first occurance in a string.
strrpos() => 用于查找字符串中第一次出现的位置。
回答by user628176
function getStringsBetween($str, $start='[', $end=']', $with_from_to=true){
$arr = [];
$last_pos = 0;
$last_pos = strpos($str, $start, $last_pos);
while ($last_pos !== false) {
$t = strpos($str, $end, $last_pos);
$arr[] = ($with_from_to ? $start : '').substr($str, $last_pos + 1, $t - $last_pos - 1).($with_from_to ? $end : '');
$last_pos = strpos($str, $start, $last_pos+1);
}
return $arr; }
this is a little improvement to the previous answer that will return all patterns in array form:
这是对先前答案的一点改进，它将以数组形式返回所有模式：
getStringsBetween('[T]his[] is [test] string [pattern]') will return:
getStringsBetween('[T]his[] is [test] string [pattern]') 将返回：
回答by Wiktor Stribi?ew
The already posted regex solutions - \((.*?)\)and \(([^\)]+)\)- do not return the innermoststrings between an open and close brackets. If a string is Text (abc(xyz 123)they bothreturna (abc(xyz 123)as a whole match, and not (xyz 123).
已经发布的正则表达式解决方案 -\((.*?)\)并且\(([^\)]+)\)- 不返回左括号和右括号之间的最里面的字符串。如果一个字符串是Text (abc(xyz 123)他们都返回一个(abc(xyz 123)作为一个完整的匹配，而不是(xyz 123)。
The pattern that matches substrings (use with preg_matchto fetch the first and preg_match_allto fetch all occurrences) in parentheses without other open and close parentheses in between is, if the match should include parentheses:
匹配括号中的子字符串（用于preg_match获取第一个和preg_match_all获取所有出现的）的模式，中间没有其他左括号和右括号，如果匹配应该包含括号：
\([^()]*\)
Or, you want to get values without parentheses:
或者，您想获得不带括号的值：
\(([^()]*)\) // get Group 1 values after a successful call to preg_match_all, see code below
\(\K[^()]*(?=\)) // this and the one below get the values without parentheses as whole matches
(?<=\()[^()]*(?=\)) // less efficient, not recommended
Replace *with +if there must be at least 1 char between (and ).
更换*用+，如果必须有至少1字符之间(和)。
Details:
详情：
\(- an opening round bracket (must be escaped to denote a literal parenthesis as it is used outside a character class)[^()]*- zero or morecharacters other than(and)(note these(and)do not have to be escaped inside a character class as inside it,(and)cannot be used to specify a grouping and are treated as literal parentheses)\)- a closing round bracket (must be escaped to denote a literal parenthesis as it is used outside a character class).
\(- 一个左圆括号（必须转义以表示文字括号，因为它在字符类之外使用）[^()]*-除and之外的零个或多个字符（注意这些，不必像在字符类内部那样在字符类内部转义，并且不能用于指定分组并被视为文字括号）()()()\)- 结束圆括号（必须转义以表示文字括号，因为它在字符类之外使用）。
The \(\Kpart in an alternative regex matches (and omits from the match value (with the \Kmatch reset operator). (?<=\()is a positive lookbehind that requires a (to appear immediately to the left of the current location, but the (is not added to the match value since lookbehind (lookaround) patterns are not consuming. (?=\()is a positive lookahead that requires a )char to appear immediately to the right of the current location.
\(\K替代正则表达式中的部分匹配(并从匹配值中省略（使用\K匹配重置运算符）。(?<=\()是一个正向后视，需要 a(立即出现在当前位置的左侧，但(不会添加到匹配值中，因为后视（环视）模式不消耗。(?=\()是一个正向前瞻，需要一个)字符立即出现在当前位置的右侧。
$fullString = 'ignore everything except this (text) and (that (text here))';
if (preg_match_all('~\(([^()]*)\)~', $fullString, $matches)) {
print_r($matches[0]); // Get whole match values
print_r($matches[1]); // Get Group 1 values
}
Output:
输出：
Array ( [0] => (text) [1] => (text here) )
Array ( [0] => text [1] => text here )
回答by rüff0
i think this is the fastest way to get the words between the first parenthesis in a string.
我认为这是在字符串中的第一个括号之间获取单词的最快方法。
$string = 'ignore everything except this (text)';
$string = explode(')', (explode('(', $string)[1]))[0];
echo $string;
