字符串到数组，用新行和括号分隔

Question

我有一个很大的字符串块，我需要根据它们是用方括号括起来还是用换行符分隔成数组。

输入：

[this is block
this is also same "block"
this is same block

another same block]
new block!
another new block!
[this is new block
this is also a new block]

我尝试过的许多事情之一：

$block_lines = preg_split('/\[([^]]+)\]|\r/', $block_content);

预期结果：

Array
(
  [0] => 'this is block
  this is also same "block"
  this is same block

  another same block'
  [1] => 'new block!'
  [2] => 'another new block!'
  [3] => 'this is new block
  this is also a new block'
)

实际结果：

Array
(
  [0] => 'new block!'
  [1] => 'another new block!'
  [2] => ''
)

Answer 1

首先匹配所有方括号匹配项（可能包含新行），否则匹配单行。

在这种情况下，我更喜欢 preg_match_all() 而不是 preg_split() 的原因是，简单来说，您实际上并不是要执行动态爆炸，而是要找到匹配项。

代码：(Demo)

$text = '[this is block
this is also same "block"
this is same block

another same block]
new block!
another new block!
[this is new block
this is also a new block]';

var_export(preg_match_all('~\[[^\]]*]|.+~', $text, $matches) ? $matches[0] : 'nothing');

输出：

array (
  0 => '[this is block
this is also same "block"
this is same block

another same block]',
  1 => 'new block!',
  2 => 'another new block!',
  3 => '[this is new block
this is also a new block]',
)

Answer 2

您可以在 preg_split:

中使用此正则表达式

/\[([^]]+)]|\R/

它将字符串拆分为 [ 和 ] 内的字符串或换行符。通过使用 PREG_SPLIT_DELIM_CAPTURE 标志，我们也可以捕获 [] 的内容：

$string = '[this is block
this is also same "block"
this is same block

another same block]
new block!
another new block!
[this is new block
this is also a new block]';
print_r(preg_split('/\[([^]]+)]|\R/', $string, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE));

输出：

Array ( 
    [0] => this is block 
this is also same "block" 
this is same block

another same block
    [1] => new block!
    [2] => another new block!
    [3] => this is new block
this is also a new block
)

Demo on 3v4l.org

Answer 3

或者，要更改逻辑的措辞，您希望在所有不在方括号表达式内的换行符上展开。您可以使用 (*SKIP)(*FAIL) 来匹配和忽略括号中的表达式，并在所有通过过滤器的换行符上爆炸。

代码：(Demo)

var_export(preg_split('~\[[^\]]*](*SKIP)(*FAIL)|\R~', $text));

输出：

array (
  0 => '[this is block
this is also same "block"
this is same block

another same block]',
  1 => 'new block!',
  2 => 'another new block!',
  3 => '[this is new block
this is also a new block]',
)

字符串到数组，用新行和括号分隔

String to array, split by new lines and brackets

php

regex

pcre

preg-match