PHP str_replace replace spaces with underscores

Question

Is there a reason that I'm not seeing, why this doesn't work?

    $string = $someLongUserGeneratedString;
    $replaced = str_replace(' ', '_', $string);
    echo $replaced;

The output still includes spaces... Any ideas would be awesome

score 205 · Accepted Answer · edited Nov 07 '13 at 12:37

205

I'll suggest that you use this as it will check for both single and multiple occurrence of white space (as suggested by Lucas Green).

$journalName = preg_replace('/\s+/', '_', $journalName);

instead of:

$journalName = str_replace(' ', '_', $journalName);

edited Nov 07 '13 at 12:37

neilco

answered Oct 03 '12 at 08:31

Laurent Brieu

It uses a [Regular Expression](http://www.regular-expressions.info/) to match a class of strings in a given pattern, and replaces it with a substitution sequence when matched. – Lucas Green Oct 03 '12 at 08:48
2

There is a bug in this version, it will only match groups of more than one space. – Lucas Green Oct 03 '12 at 08:50
3

@LucasGreen, you right ! Correct one is : preg_replace('/\s+/', '_', $journalName); – Laurent Brieu Oct 03 '12 at 08:52
4

you probably want trim as well: preg_replace('/\s+/', '_', trim($journalName)); – Andrew Oct 12 '16 at 12:48
For UTF-8 encoding use ```preg_replace('/\s+/u', '_', $journalName)``` – Alliswell May 06 '21 at 08:50

score 23 · Answer 2 · answered Oct 03 '12 at 08:31

23

Try this instead:

$journalName = preg_replace('/\s+/', '_', $journalName);

Explanation: you are most likely seeing whitespace, not just plain spaces (there is a difference).

answered Oct 03 '12 at 08:31

Lucas Green

score 12 · Answer 3 · answered Feb 25 '15 at 05:13

12

For one matched character replace, use str_replace:

$string = str_replace(' ', '_', $string);

For all matched character replace, use preg_replace:

$string = preg_replace('/\s+/', '_', $string);

answered Feb 25 '15 at 05:13

Ravi Patel

score -2 · Answer 4 · answered Jan 22 '16 at 06:11

-2

Try this instead:

$journalName = str_replace(' ', '_', $journalName);

to remove white space

answered Jan 22 '16 at 06:11

IsaacP

2

How does this differ from the code provided in the question (other than variable names)? `$replaced = str_replace(' ', '_', $string);` – Ash Oldershaw Mar 24 '21 at 16:22

4 Answers4