php - Remove only whitespaces between words, but leave

Question

I am using PHP 7.4.1 and want to remove double/triple/n-th whitespaces only between two words.

I tried:

<?php

$str = "Hello World!



This is my  input  string.";

$str1 = preg_replace('/ss+/', ' ', $str);

echo $str1;

echo "
############################### 
";

$str2 = preg_replace('/[s]+/mu', ' ', $str);

echo $str2;

echo "
############################### 
";

This on the one hand removes the whitespace, but on the other hand removes the two .

I would like to have the following output:

Hello World!


This is my input string.

Any suggestions what I am doing wrong?

I appreciate your replies!

question from:https://stackoverflow.com/questions/65861804/remove-only-whitespaces-between-words-but-leave-n

Answer 1

Use word boundaries:

$str = "Hello World!
This is my  input  string.";
$output = preg_replace("/[ ]{2,}/", " ", $str);
echo $str . "
" . $output;

This prints:

Hello World!
This is my  input  string.
Hello World!
This is my input string.