仅替换字符串中的所有点，而不替换数字值

Question

I want to replace all occurrence of dot (.) in a string but not a digits or numeric value. I have given example

STRING : 10.10.2015 11.30 09/2007 83 HELLO.HOW.ARE.YOU $.###
OUTPUT : 10.10.2015 11.30 09/2007 83 HELLO HOW ARE YOU $ ###

I tried using preg_replace in php

Answer 1

Use a non-capturing lookbehind group to test if the previous character is a digit or not

$string = '10.10.2015 11.30 09/2007 83 HELLO.HOW.ARE.YOU $.###';
$result = preg_replace('/(?<=[^\d])\./', ' ', $string);
var_dump($result);

explanation

(?<=[^\d])\.
 -------- --
     ^    ^
     |    |
     |    ------------------  Escape the `.` so we're working with a literal
     |                          dot rather than "any character"
     |
     -----------------------  Look for any preceding non-digit character
                                but don't include it in the replace group

Answer 2

I am not a preg_replace guru, so I wrote a function, which will split your string to array, then check, if any . exist and if it found a dot, it will check, if is the dot located between 2 numbers. If it is, my function will replace . with :

function removeDots($string) {
    $arr = str_split($string);
    foreach($arr as $key => $val) {
        if($val == ".") {
            if(!is_numeric($arr[$key-1]) && !is_numeric($arr[$key+1])) {
                $arr[$key] = " ";
            }
        }
    }
    return implode($arr);
}

and here is the result:

$str = "STRING : 10.10.2015 11.30 09/2007 83 HELLO.HOW.ARE.YOU $.###";
echo removeDots($str);

OUTPUT:

STRING : 10.10.2015 11.30 09/2007 83 HELLO HOW ARE YOU $ ###