check if the string begin with euro/pound symbol - php

Question

I'm trying to check if a string is start with '€' or '£' in PHP.
Below are the codes
$text = "€123";
if($text[0] == "€"){
echo "true";
}
else{
echo "false";
}
//output false
If only check a single char, it works fine
$symbol = "€";
if($symbol == "€"){
echo "true";
}
else{
echo "false";
}
// output true
I have also tried to print the string on browser.
$text = "€123";
echo $text; //display euro symbol correctly
echo $text[0] //get a question mark
I have tried to use substr(), but the same problem occurred.

Answer 1

Characters, such as '€' or '£' are multi-byte characters. There is an excellent article that you can read here. According to the PHP docs, PHP strings are byte arrays. As a result, accessing or modifying a string using array brackets is not multi-byte safe, and should only be done with strings that are in a single-byte encoding such as ISO-8859-1.
Also make sure your file is encoded with UTF-8: you can use a text editor such as NotePad++ to convert it.
If I reduce the PHP to this, it works, the key being to use mb_substr:
<?php
header ('Content-type: text/html; charset=utf-8');
$text = "€123";
echo mb_substr($text,0,1,'UTF-8');
?>
Finally, it would be a good idea to add the UTF-8 meta-tag in your head tag:
<meta charset="utf-8">

Answer 2

I suggest this as the easiest solution to you. Convert the symbols to their unicode identifiers using htmlentities().
htmlentities($text, ENT_QUOTES, "UTF-8");
Which will either give you £ or €. Now that allows you to run a switch() {case:} statement to check. (Or your if statements)
$symbols = explode(";", $text);
switch($symbols[0]) {
case "&pound":
echo "It's Pounds";
break;
case "&euro":
echo "It's Euros";
break;
}
Working Example

Answer 3

This happens because you’re using a multi-byte character encoding (probably UTF-8) in which both € and £ are recorded using multiple bytes. That means that "€" is a string of three bytes, not just one.
When you use $text[0] you're getting only the first byte of the first character, and so it doesn't match the three bytes of "€". You need to get the first three bytes instead, to check whether one string starts with another.
Here’s the function I use to do that:
function string_starts_with($string, $prefix) {
return substr($string, 0, strlen($prefix)) == $prefix;
}
The question mark appears because the first byte of "€" isn’t enough to encode a whole character: the error is indicated by ‘�’ when available, otherwise ‘?’.