How do I select specific numbers from a string?

I am trying to pass a value along to my php form handler to take the field and select the 4th and 5th number out of the string. The purpose for this is for a person to type in their model number and based on the two numbers it will tell them what size of a unit they have.

Example: YAZA36VX1W

Say this is a model number... I need to be able to tell what the bolded numbers are in order to do what I am wanting to do with this form. I'm thinking it is going to have something to do with the strip function but I don't know.

Brandon

would I need to use count() somehow in this? I don't really know where to start.

Actually scratch this. I talked to my boss and the number that I'm looking for isn't necessarily in the same place every time. I need to find a string inside of a string.

I need to look for the numbers 24, 30, 36, 42, 48, 60

PHP Code:

if (how do i calculate this == '24') {
echo "You have a 2 ton system.";
} else if (how do i calculate this == '30') {
echo "You have a 2.5 ton system.";
} else if (how do i calculate this == '36') {
echo "You have a 3 ton system.";
} else if (how do i calculate this == '42') {
echo "You have a 3.5 ton system.";
} else if (how do i calcualte this == '46') {
echo "You have a 4 ton system.";
} else if (how do i calculate this == '60') {
echo "You have a 5 ton system.";
} 


This is kinda what I want to do.. only I don't know how to determine if a string contains a certain value.

Example:
Y2436A15
Y24A1536
Y3624A15

No matter where the number is, it will recognize that it is part of the string.

I think strstr() is what you're looking for.

http://us.php.net/manual/en/function.strstr.php

Edit:

I forgot to mention: this is one of the few cases in PHP where datatype is important. Make sure you use strings as input or you might get some unexpected behavior:

PHP Code:

strstr($subject, '42'); //correct
strstr($subject, 42); //incorrect 


Thank you, this helped me out a lot.