PHP in_array() always returning false

Question

PHP is always returning false when I use in_array(), and whether it is or isn't in the array doesn't matter. For example:

$list = 'test
list
example';
$list_arr = array();
$list_arr = explode("\n",$list);
if (in_array('test',$list_arr)) {
    echo 'Found';
}
else {
    echo 'Not Found';
}

Returns 'Not Found' even though 'test' is a value in the array

$list = 'test
list
example';
$list_arr = array();
$list_arr = explode("\n",$list);
if (in_array('qwerty',$list_arr)) {
    echo 'Found';
}
else {
    echo 'Not Found';
}

Returns 'Not Found', as it should

Why is it returning false when it should be true? Please give any suggestions. The list I am actually using has more than 10K of values and therefore I just shortened it here.

What OS are you using? In windows, an end-of-line is actually two characters: \r\n, so splitting it on \n will give you 'text\r', 'list\r' and 'example'. — Bart Friederichs
– Bart Friederichs, Commented Jul 16, 2012 at 20:26

Mathieu Dumoulin · Accepted Answer · 2012-07-16 20:26:50Z

11

If you are using this exact example and are coding on a Windows PC, the problem comes from the fact that Windows stores line feeds using:

\r\n

Thus, when you split on \n only you keep an invisible \r at the end of your items and they don't match for that reason.

answered Jul 16, 2012 at 20:26

Mathieu Dumoulin

12.3k7 gold badges47 silver badges71 bronze badges

Sign up to request clarification or add additional context in comments.

9 Comments

Ethan H Over a year ago

I am on linux, however that did fix the problem

Esailija Over a year ago

It can be configured in the editor, which should not be notepad

Ethan H Over a year ago

I also use Windows to code it, it is just running on a linux server. Could that be why?

Esailija Over a year ago

I am confused, didn't you just say you are using linux? If you use notepad++, configure it to save newlines as '\n' (UNIX). See stackoverflow.com/questions/8195839/…

Mathieu Dumoulin Over a year ago

As Esailija said, the source of your file has to be coded in a Linux format if you want to use PHP_EOL on linux. But if your server runs on Windows, then make sure your NotePad++ is configured for Windows style line endings.

|

gen_Eric · Accepted Answer · 2012-07-16 20:26:31Z

8

Your list is actually separated by \r\n, not just \n.

$list_arr = explode("\r\n",$list);

answered Jul 16, 2012 at 20:26

gen_Eric

228k42 gold badges304 silver badges343 bronze badges

6 Comments

Mathieu Dumoulin Over a year ago

Beat me to it by what... 4 seconds?

Ariel Over a year ago

Right, and when you separate by "\r" you end up with "text\r" as the string - so try putting that in the in_array() just to see.

gen_Eric Over a year ago

@MathieuDumoulin: I'm a ninja :P

Mathieu Dumoulin Over a year ago

No you're a @Rocket, much faster!

gen_Eric Over a year ago

@MathieuDumoulin: Rocket Ninja.

|

Mike Brant · Accepted Answer · 2012-07-16 20:35:57Z

That is a pretty odd way of getting values into a list. So I am assuming that you are ultimately trying to lines from a separate file into an array. In which case you would just do

file('path/to/file');

To read each line into a separate array item.

Where the file referenced looks like:

test
list
example

If you know the values up front like in your code sample, you should just put them into an array rather than reading them from a string.

If you simply must read the values from a string, I would suggest using PHP_EOL constant to define your line breaks. Like this:

$list = 'test' . PHP_EOL . 'list' . PHP_EOL . 'example';
$list_arr = explode(PHP_EOL, $list);

The PHP_EOL constant is going to give you a much better platform-independent way of getting values defining your line breaks.

Bart Friederichs · Accepted Answer · 2022-11-09 08:10:31Z

1

As already stated, Windows uses \r\n as end of line characters. Unix uses \n and Mac uses \r. To make portable code, use the PHP_EOL constant to explode your string:

$list_arr = explode(PHP_EOL, $list)

That way, you are sure it always works correctly.

edited Nov 9, 2022 at 8:10

answered Jul 16, 2012 at 20:29

Bart Friederichs

33.8k16 gold badges112 silver badges219 bronze badges

2 Comments

Mathieu Dumoulin Over a year ago

Not true, as Windows will store EOL as \r\n but if you run it on a linux pc, it will be \n only: ca3.php.net/manual/en/reserved.constants.php

Bart Friederichs Over a year ago

@MathieuDumoulin the provided link does not state that. It just says "the right end-of-line character" for the platform. My solution wouldn't work if you'd use a Windows terminated editor on a Unix platform.

Collectives™ on Stack Overflow

PHP in_array() always returning false

4 Answers 4

9 Comments

6 Comments

Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

9 Comments

6 Comments

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related