Php pcre regex - splitting text by backslashes

Question

I need this string: "test1 test2-test3\test4" to be split into 4 strings:

Array
(
    [0] => test1
    [1] => test2
    [2] => test3
    [3] => test4
)

What am I doing wrong?

I've tried this:

<?php

    $aa = 'test1 test2-test3\test4';
    $arr = preg_split('#[\s|\|-]+#u', $aa);
    print_r($arr);

?>
Array
(
    [0] => test1
    [1] => test2
    [2] => test3\test4
)

And this:

<?php

    $aa = 'test1 test2-test3\test4';
    $arr = preg_split('#[\s|\\|-]+#u', $aa);
    print_r($arr);

?>
Array
(
    [0] => test1
    [1] => test2
    [2] => test3\test4
)

To no avail. For some reason it doesn't split by backslash- why?

Extra backslash needed in PHP regexp pattern

AbraCadaver
– AbraCadaver

2014-04-03 19:27:15 +00:00
Commented Apr 3, 2014 at 19:27 — AbraCadaver
– AbraCadaver, Commented Apr 3, 2014 at 19:27

anubhava · Accepted Answer · 2014-04-03 19:26:57Z

2

You don't need to place pipe inside character class.

You can use:

$aa = 'test1 test2-test3\test4';
$arr = preg_split('#[-\s\\\\]+#u', $aa);
print_r($arr);

OUTPUT:

Array
(
    [0] => test1
    [1] => test2
    [2] => test3
    [3] => test4
)

answered Apr 3, 2014 at 19:26

anubhava

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1 Comment

anubhava Over a year ago

Pipe is also treated as a literal pipe inside character class not OR.

Sabuj Hassan · Accepted Answer · 2014-04-03 19:27:35Z

2

Your first mistake is not an error, but it looks odd. You do not need to place pipe(|) inside the character class []. Simply place the character inside []

If you are dealing with backslash, then you have to use several slashes, one for the slash itself, and another two for the escape character.

Here it is based on above lines:

$arr = preg_split('#[\s\\\-]+#u', $aa);

answered Apr 3, 2014 at 19:27

Sabuj Hassan

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Comments

Shankar Narayana Damodaran · Accepted Answer · 2014-04-03 19:31:39Z

2

Use this ..

  $arr = preg_split('#[\s|\\\|-]+#u', $aa);         
                           ^^ //<-------------- Add two more backslashes

OUTPUT :

Array
(
    [0] => test1
    [1] => test2
    [2] => test3
    [3] => test4
)

enter image description here

edited Apr 3, 2014 at 19:31

answered Apr 3, 2014 at 19:26

Shankar Narayana Damodaran

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Comments

AbraCadaver · Accepted Answer · 2014-04-03 19:29:51Z

1

Try three slashes \:

    $arr = preg_split('#[\s|\\\|-]+#u', $aa);

And you don't need the alternation in the character class:

    $arr = preg_split('#[\s\\\-]+#u', $aa);

edited Apr 3, 2014 at 19:29

answered Apr 3, 2014 at 19:24

AbraCadaver

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2 Comments

Dannyboy Over a year ago

gotcha. extra backslash for the win.

AbraCadaver Over a year ago

I posted a link in comments after the answer. Seems in some or all cases 4 \\\\ is the most correct.

Jessica · Accepted Answer · 2014-04-03 19:25:31Z

1

Try (\w+)? It seems to do exactly what you need in debuggex. Click through to see demo.

(\w+)

Regular expression visualization

Debuggex Demo

answered Apr 3, 2014 at 19:25

Jessica

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