PHP preg_split将分隔符保存在不同的元素中

Question

I'm trying to split a string into an array of parts.

String Example...

The quick brown fox [[random text here]] and then [[a different text here]]

Text between the square brackets will change and cannot be determined ahead of time. The preg_split I have so far will split, but it places the delimiters in other elements in the produced array, not the element I want it to be in.

$page_widget_split = preg_split('@(?<=\[\[)(.*?)(?=\]\])@', $page_content,-1, PREG_SPLIT_DELIM_CAPTURE);

This produces something like this...

[0] => "The quick brown fox [[",
[1] => "random text here]]",
[2] => " and then [[",
[3] => "a different text here]]"

The desired result would look like this...

[0] => "The quick brown fox",
[1] => "[[random text here]]",
[2] => " and then ",
[3] => "[[a different text here]]"

As I'm far from understanding Regex, could someone please take a look and tell me what I'm missing in the regex ?

Answer 1

This will get you pretty close

 $page_content = 'the quick brown fox [[random text here]] and then [[a different text here]]';

 print_r(preg_split('/(\[\[[^\]]+\]\])/', $page_content, -1, PREG_SPLIT_DELIM_CAPTURE|PREG_SPLIT_NO_EMPTY));

The thing to remember is that this is the delimiter (\[\[[^\]]+\]\])

Output:

Array
(
    [0] => the quick brown fox 
    [1] => [[random text here]]
    [2] =>  and then 
    [3] => [[a different text here]]
)

Sandbox

When i say pretty close, I do mean really pretty close...

The regex is pretty straight forward, capture 2 [ then anything but a ] then 2 of those ]. Which makes our delimiter, which we then capture. No empty flag is nice too.

Enjoy!

UPDATE

but it fails on " here is my table [[{"widget":"table","id":"1","title": "Views Table", "columns": []}]] and this is more text"...Note the "[]" under the 'columns'

To handle that you will need a recursive regex pattern using (?R), like this:

$page_content = 'here is my table [[{"widget":"table","id":"1","title": "Views Table", "columns": []}]] and this is more text [someother bracket]';

print_r(preg_split('/(\[(?:[^\[\]]|(?R))*\])/', $page_content, -1, PREG_SPLIT_DELIM_CAPTURE|PREG_SPLIT_NO_EMPTY));

Output:

Array
(
    [0] => here is my table 
    [1] => [[{"widget":"table","id":"1","title": "Views Table", "columns": []}]]
    [2] =>  and this is more text 
    [3] => [someother bracket] //single bracket capture
)

Sandbox

I won't pretend, this is kind of at the edge of my knowledge of regex, I should note this matches single brackets and not specifically double ones. You could try something like this /(\[(\[(?:[^\[\]]|(?2))*\])\])/ the (?2) is like (?R) but for a specific capture group. Which this works to match only [[ ... ]] while keeping the inner nesting. But the issue is, then you have the capture duplicated, so you wind up with this:

Array
(
    [0] => here is my table 
    [1] => [[{"widget":"table","id":"1","title": "Views Table", "columns": []}]]
    [2] => [{"widget":"table","id":"1","title": "Views Table", "columns": []}]
    [3] =>  and this is more text [someother bracket]
)

Notice how it doesn't capture [someother bracket], but it captures the other one 2 times. There may be a way around that, but i can't think of it.

Rather or not capturing single bracket pairs is an issue I don't know.

But I have used this before, mainly for matching, matched pairs of " or ( ) but it's the same concept.

The only other solution would be to make a lexer/parser for it, I have some examples of how do do that on my GitHub account. Regex (by itself) is not suited to nested elements. Most any regex solution will fail on nesting.