用分隔符分割字符串，但如果它被转义了就不行

How can I split a string by a delimiter, but not if it is escaped? For example, I have a string:

如何用分隔符分割一个字符串，但如果它被转义了呢?例如，我有一个字符串:

1|2\|2|3\\|4\\\|4

The delimiter is | and an escaped delimiter is \|. Furthermore I want to ignore escaped backslashes, so in \\| the | would still be a delimiter.

分隔符是|，转义分隔符是\|。此外，我想忽略转义的反斜杠，所以在\|中，|仍然是一个分隔符。

So with the above string the result should be:

因此，对于上面的字符串，结果应该是:

[0] => 1
[1] => 2\|2
[2] => 3\\
[3] => 4\\\|4

5 个解决方案

#1

107

Use dark magic:

使用黑魔法:

$array = preg_split('~\\\\.(*SKIP)(*FAIL)|\|~s', $string);

\\\\. matches a backslash followed by a character, (*SKIP)(*FAIL) skips it and \| matches your delimiter.

\ \ \ \。匹配一个后跟字符的反斜杠，(*SKIP)(*FAIL)跳过它，\|匹配您的分隔符。

#2

Instead of split(...), it's IMO more intuitive to use some sort of "scan" function that operates like a lexical tokenizer. In PHP that would be the preg_match_all function. You simply say you want to match:

与split(…)不同，使用某种类似词汇标记器的“扫描”功能在我看来更直观。在PHP中，这是preg_match_all函数。你只是说你想匹配:

something other than a \ or |
不只是一个\或|
or a \ followed by a \ or |
或者跟着一个\或|
repeat #1 or #2 at least once
至少重复1或2次

The following demo:

下面的演示:

$input = "1|2\\|2|3\\\\|4\\\\\\|4";
echo $input . "\n\n";
preg_match_all('/(?:\\\\.|[^\\\\|])+/', $input, $parts);
print_r($parts[0]);

will print:

将打印:

1|2\|2|3\\|4\\\|4

Array
(
    [0] => 1
    [1] => 2\|2
    [2] => 3\\
    [3] => 4\\\|4
)

#3

Recently I devised a solution:

最近我想出了一个解决方案:

$array = preg_split('~ ((?<!\\\\)|(?<=[^\\\\](\\\\\\\\)+)) \| ~x', $string);

But the black magic solution is still three times faster.

但是黑魔法解决方案仍然快了三倍。

#4

For future readers, here is a universal solution. It is based on NikiC's idea with (*SKIP)(*FAIL):

对于未来的读者，这里有一个通用的解决方案。基于NikiC的想法(*SKIP)(*FAIL):

function split_escaped($delimiter, $escaper, $text)
{
    $d = preg_quote($delimiter, "~");
    $e = preg_quote($escaper, "~");
    $tokens = preg_split(
        '~' . $e . '(' . $e . '|' . $d . ')(*SKIP)(*FAIL)|' . $d . '~',
        $text
    );
    $escaperReplacement = str_replace(['\\', '$'], ['\\\\', '\\$'], $escaper);
    $delimiterReplacement = str_replace(['\\', '$'], ['\\\\', '\\$'], $delimiter);
    return preg_replace(
        ['~' . $e . $e . '~', '~' . $e . $d . '~'],
        [$escaperReplacement, $delimiterReplacement],
        $tokens
    );
}

Make a try:

试一试:

// the base situation:
$text = "asdf\\,fds\\,ddf,\\\\,f\\,,dd";
$delimiter = ",";
$escaper = "\\";
print_r(split_escaped($delimiter, $escaper, $text));

// other signs:
$text = "dk!%fj%slak!%df!!jlskj%%dfl%isr%!%%jlf";
$delimiter = "%";
$escaper = "!";
print_r(split_escaped($delimiter, $escaper, $text));

// delimiter with multiple characters:
$text = "aksd()jflaksd())jflkas(('()j()fkl'()()as()d('')jf";
$delimiter = "()";
$escaper = "'";
print_r(split_escaped($delimiter, $escaper, $text));

// escaper is same as delimiter:
$text = "asfl''asjf'lkas'''jfkl''d'jsl";
$delimiter = "'";
$escaper = "'";
print_r(split_escaped($delimiter, $escaper, $text));

Output:

输出:

Array
(
    [0] => asdf,fds,ddf
    [1] => \
    [2] => f,
    [3] => dd
)
Array
(
    [0] => dk%fj
    [1] => slak%df!jlskj
    [2] => 
    [3] => dfl
    [4] => isr
    [5] => %
    [6] => jlf
    )
Array
(
    [0] => aksd
    [1] => jflaksd
    [2] => )jfl'kas((()j
    [3] => fkl()
    [4] => as
    [5] => d(')jf
)
Array
(
    [0] => asfl'asjf
    [1] => lkas'
    [2] => jfkl'd
    [3] => jsl
)

Note: There is a theoretical level problem: implode('::', ['a:', ':b']) and implode('::', ['a', '', 'b']) result the same string: 'a::::b'. Imploding can be also an interesting problem.

注意:有一个理论水平问题:内爆(“::”,[':',':b '])和内爆(“::”,[‘一个’,”,' b '])结果相同的字符串:::::b。内爆也是一个有趣的问题。

#5

-1

Regex is painfully slow. A better method is removing escaped characters from the string prior to splitting then putting them back in:

正则表达式是缓慢的。更好的方法是从字符串中删除转义字符，然后再将其放回:

$foo = 'a,b|,c,d||,e';

function splitEscaped($str, $delimiter,$escapeChar = '\\') {
    //Just some temporary strings to use as markers that will not appear in the original string
    $double = "\0\0\0_doub";
    $escaped = "\0\0\0_esc";
    $str = str_replace($escapeChar . $escapeChar, $double, $str);
    $str = str_replace($escapeChar . $delimiter, $escaped, $str);

    $split = explode($delimiter, $str);
    foreach ($split as &$val) $val = str_replace([$double, $escaped], [$escapeChar, $delimiter], $val);
    return $split;
}

print_r(splitEscaped($foo, ',', '|'));

which splits on ',' but not if escaped with "|". It also supports double escaping so "||" becomes a single "|" after the split happens:

它在'，但如果用"|"逃脱的话。它也支持双转义，所以“||”在分割后成为单个“|”:

Array ( [0] => a [1] => b,c [2] => d| [3] => e )

#1

107