PHP preg_replace 表达式满足以下要求？

Question

Input text:

 Hello, raj's            dogs age                              is 18. "

Output:

Hello, raj's dogs age is 18.

Requirements:

1. Remove Extra space between words.
2. allow Capital & Small letter & number & dot(.) & single quotes(').
3. Do Not allow space at starting and ending of string.

Answer 1

Replace multiples spaces with one space.

echo trim(preg_replace('/\h+/', ' ', ' Hello, raj\'s           dogs age                     is 18. '));

The \\h is a horizontal whitespace (tab/space). The + after means at least one must be preset. The space in the replacement replaces the one or more with just one. PHP's trim can then be used to remove leading/trailing spaces.

Answer 2

use str_replace() function

$string = " Hello, raj's           dogs age                     is 18. ";
$result=str_replace(' ', ' ', $string);
echo $result;

Answer 3

Try replacing two or more whitespace characters with just a single space:

$string = " Hello, raj's           dogs age                     is 18. ";
$result = trim(preg_replace('/\s{2,}/', ' ', $string));
echo $result;

This prints:

Hello, raj's dogs age is 18.