For some odd reason, below function returns 11 when input 2, where I would expect it to return 1. What is wrong?
<?php
function convert($v){
$arr = array(
2 => 1,
21 => 1,
3 => 2,
6 => 2,
11 => 2,
12 => 2,
4 => 3,
14 => 3,
19 => 3,
9 => 5,
1 => 11,
10 => 11,
22 => 12,
23 => 13,
14 => 14,
);
$ret = str_replace(array_keys($arr), array_values($arr), $v);
return $ret;
}
echo convert(2); // echoes 11
?>
You're using the wrong function, try strtr instead:
function convert($v){
$arr = array(
2 => 1,
21 => 1,
...
23 => 13,
14 => 14,
);
$ret = strtr($v, $arr);
return $ret;
}
And in any case: If you find something strange with a PHP function, visit it's manual page and read it, for str_replace a specific example is given that explains your problem: Example #2 Examples of potential str_replace() gotchas
This is because str_replace() processes each replacement from left to right. So when it matches on the key 2 in your array, it is changed to a 1. After that, it hits the key 1 and is changed to an 11. As a short example:
function convert($v) {
$arr = array(
1 => 2,
2 => 3,
3 => 'cat',
);
$ret = str_replace(array_keys($arr), array_values($arr), $v);
return $ret;
}
echo convert(1); //cat is echoed
So in this case the 1 goes to a 2, then that 2 to a 3, and finally the 3 to cat.
