how to do reg_replace +1?

<?php
$keyword="aaaaaaa";
$i++;


$keyworda = preg_replace("/a/", "a$i", "$keyword");

echo "$keyworda";
?>

PHP:

this is my stupid code.
the result is "a1a1a1a1a1a1a1"

how to do? get result is "a1a2a3a4a5a6a7"

thank you

 

Assuming your string/keyword doesn't consist only of the letter 'a', then theirs many ways of achieving this.

<?php

$str = 'aaaaaaa';

$chars = str_split($str);

$result = NULL;

foreach ($chars as $key => $char) {
$result .= $char.($key + 1);
}

echo $result;

PHP:

or:

<?php

$str = 'aaaaaaa';

$chars = str_split($str);

$result = NULL;

for ($i = 0; $i < strlen($str); $i++) {
$result .= $chars[$i] . ($i + 1);
}

echo $result;

PHP:

or:

<?php

$str = 'aaaaaaa';

$result = array_map(function($char) {
global $i;
++$i;
return $char.$i;
}, str_split($str));

echo implode('', $result);

PHP:

 

is possible via preg_replace?
also, i'd like to replace anything possbile keywords.

like below
$keyworda = preg_replace("/<b>(.*)</b>/", "<b>$i</b>", "$keyword");

find all <b>(.*)</b> and replace to be <b>number+1</b>
<b>com</b> --> <b>1</b>
<b>net</b> --> <b>2</b>
<b>org</b> --> <b>3</b>.....etc

thanks for help.

 

This works:

$i=0;
$keyworda = preg_replace_callback("~<b>(.*?)</b>~", create_function('','global $i; return ++$i;'), $keyword);

PHP:

$keyword = "<b>a</b>B<b>a</b>C<b>a</b>D<b>a</b><b>a</b><b>a</b><b>a</b>";
Outputs:
1B2C3D4567

 

If you use create_function within a pattern with more than a couple of matches, it's more efficient to create an actual function and pass that function to preg_replace_callback. preg_replace_callback will invoke create_function and create the anonymous function every time there's a match. For the original example string of "aaaaaaa", the anonymous function would be created 7 times. If this is an article or something where you may have a couple of hundred matches, this can be a problem.

 

thanks for everyone's help.
especially ssmm987 help me out.

thank you