PHP count of occurrences of characters of a string within another string

Question

Let's say I have two strings.

$needle = 'AGUXYZ';
$haystack = 'Agriculture ID XYZ-A';

I want to count how often characters that are in $needle occur in $haystack. In $haystack, there are the characters 'A' (twice), 'X', 'Y' and 'Z', all of which are in the needle, thus the result is supposed to be 5 (case-sensitive).

Is there any function for that in PHP or do I have to program it myself?

Thanks in advance!

Answer 1

You can calculate the length of the original string and the length of the string without these characters. The differences between them is the number of matches.

Basically,

$needle = 'AGUXYZ';
$haystack = 'Agriculture ID XYZ-A';

Here is the part that does the work. In one line.

$count = strlen($haystack) - strlen(str_replace(str_split($needle), '', $haystack));

Explanation: The first part is self-explanatory. The second part is the length of the string without the characters in the $needle string. This is done by replacing each occurrences of any characters inside the $needle with a blank string.

To do this, we split $needle into an array, once character for each item, using str_split. Then pass it to str_replace. It replaces each occurence of any items in the $search array with a blank string.

Echo it out,

echo "Count = $count\n";

you get:

Count = 5