Replace certain characters in a string from array values - php

Question

I've got an array :
$arr = [5, "David"];
I've got a query :
$query = "SELECT * FROM users WHERE user_id = ? AND user_name = ?";
I want to create a logger query that takes these 2 and returns the query, manually.
logger($query, $arr); // returns : SELECT * FROM users WHERE user_id = 5 AND user_name = 'David'
I'm using eloquent's capsule manager.
I tried doing something like this but it doesn't replace anything :
function logger($query, $arr) {
foreach($arr as $a) {
is_numeric($a) ? str_replace("?",$a,$query) : str_replace("?","'".$a."'",$query);
}
return $query;
}
Why isn't this code working?

Answer 1

str_replace does not modify its argument, it returns the modified value instead. So you need to assign its output to a variable. However the problem is that str_replace will replace all occurrences of the pattern at the same time. Instead, you can use preg_replace, which has a limit parameter which can be used to tell it to replace only one occurrence of the pattern for each call. I've used a pattern for preg_replace that will ensure that only a ? on its own in the query will be replaced, in case there is a question mark elsewhere e.g. in a column alias. Change your function to this:
function logger($query, $arr) {
foreach($arr as $a) {
$query = is_numeric($a) ?
preg_replace("/(?<=\s)\?(?=\s|$)/", $a, $query, 1) :
preg_replace("/(?<=\s)\?(?=\s|$)/", "'$a'", $query, 1);
}
return $query;
}
Output:
SELECT * FROM users WHERE user_id = 5 AND user_name = 'David'
Demo on 3v4l.org

Answer 2

I found out how to do it, by using str_replace_first and assiging the value into a variable.
foreach($params as $a) {
$query = is_numeric($a) ? str_replace_first("?",$a,$query,1) : str_replace_first("?","'".$a."'",$query);
}
return $query;
str_replace_first :
function str_replace_first($search_for, $replace_with, $in) {
$pos = strpos($in, $search_for);
if($pos === false) {
return $in;
} else {
return substr($in, 0, $pos) . $replace_with . substr($in, $pos + strlen($search_for), strlen($in));
}
}