String to array, split by new lines and brackets

Question

I have large string block which I need to split into arrays based on if they're wrapped in brackets or separated by new lines.

Input:

[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]

One of the many things I've tried:

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

Expected result:

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'
)

Actual result:

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

I don't recommend preg_split() for this because you need to pair the [ with the ]. — mickmackusa
– mickmackusa ♦, Commented Dec 20, 2018 at 22:56
It looks like you are using curly braces instead of square braces in your pattern. \R will get \r\n and \n. — mickmackusa
– mickmackusa ♦, Commented Dec 20, 2018 at 23:04
To start this \{ will not match [ , it just won.t. In other words \{([^}]+)\} matches {tag} not [tag] — ArtisticPhoenix
– ArtisticPhoenix, Commented Dec 20, 2018 at 23:05
Yeah sorry about that, I tried doing a variation with curly braces in case I was getting confused with the multiple square brackets. Edited it back to the version I was trying with square brackets (still incorrect), but I've accepted the correct answer below. — daveclever
– daveclever, Commented Dec 20, 2018 at 23:15

Nick · Accepted Answer · 2018-12-20 23:01:18Z

2

You can use this regex in preg_split:

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

It splits the string on either a string of characters inside [ and ], or on a newline. By using the PREG_SPLIT_DELIM_CAPTURE flag, we can capture the contents of the [] as well:

$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));

Output:

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

answered Dec 20, 2018 at 23:01

Nick

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Comments

mickmackusa · Accepted Answer · 2018-12-22 22:26:40Z

1

Match all square braces matches first (which may contain new lines) else match a single line.

The reason that I am favoring preg_match_all() over preg_split() for this case is because in plain terms, you aren't actually intending to perform dynamic explosions but to find matches.

Code: (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');

Output:

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]',
)

edited Dec 22, 2018 at 22:26

answered Dec 20, 2018 at 23:00

mickmackusa♦

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Comments

mickmackusa · Accepted Answer · 2018-12-20 23:21:04Z

0

Alternatively, to change the phrasing of your logic, you wish to explode on all newlines that are not inside of a square bracketed expression. You can use (*SKIP)(*FAIL) to match and disregard the bracketed expressions, and explode on all newlines that make it through the filter.

Code: (Demo)

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

Output:

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]',
)

answered Dec 20, 2018 at 23:21

mickmackusa♦

49.2k13 gold badges98 silver badges165 bronze badges

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