Question

I have two variables such as:

var1 =  "z";
var2 = "A";

how can I check if var1 is after in the alphabet than var2 (in this case it should return true)?

Answer 1

I think everyone who has answered agrees that strcmp() is the right answer, but every answer provided so far will give you incorrect results. Example:

echo strcmp( "Z", "a" );

Result: -1

echo strcmp( "z", "A" );

Result: 1

strcmp() is comparing the binary (ord) position of each character, not the position in the alphabet, as you desire. If you want the correct results (and I assume that you do), you need to convert your strings to the same case before making the comparison. For example:

if( strcmp( strtolower( $str1 ), strtolower( $str2 ) ) < 0 )
{
  echo "String 1 comes before string 2";
}

Edit: you can also use strcasecmp(), but I tend to avoid that because it exhibits behavior that I’ve not taken the time to understand on multi-byte strings. If you always use an all-Latin character set, it’s probably fine.