Easiest way to replace all characters in even positions in a string.

Question

$str = "helloworld";

I want to create string

$newStr = "h l o o l ";

So as you can see i want to replace the chars in positions , 2,4,6,8,10 (assuming first character is in position 1).

I can do something like this

<?php

$str = 'helloworld';
$newStr = '';
for($i=0;$i<strlen($str);$i++) {
    if($i%2==0) {
        $newStr .=  $str[$i];
    } else {
           $newStr .= ' ';
    }
}

echo $newStr;

?>

But is there a more easier way or a one line in built function available to do this task .

Thanks in advance .

Answer 1

It is easily done with a regular expression:

echo preg_replace('/(.)./', '$1 ', $str);

The dot matches a character. Every second character is replaced with a space.

Answer 2

Firstly you can increase your counter by two, so you don't have to check if it's odd. Secondly because strings are treated like char arrays you can access a char at position $i with $str[$i].

$str = "Hello World";
$newStr = $str;
for($i = 1; $i < strlen($str); $i += 2) {
  $newStr[$i] = ' ';
}
echo $newStr;

Have a Nice day.

[Edit] Thanks ringo for the hint.

Answer 3

Try this, a little shorter then yours but is a one-liner as you asked.

$str    = 'helloworld';
$newStr = '';
for( $i = 0; $i < strlen( $str ); $i++) { $newStr .= ( ( $i % 2 ) == 0 ? $str[ $i ] : ' ' ); }
echo $newStr;