Compare two version strings in PHP

Question

How to compare two strings in version format? such that:

version_compare("2.5.1",  "2.5.2") => -1 (smaller) version_compare("2.5.2",  "2.5.2") =>  0 (equal) version_compare("2.5.5",  "2.5.2") =>  1 (bigger) version_compare("2.5.11", "2.5.2") =>  1 (bigger, eleven is bigger than two) 

Answer 1

From the PHP interactive prompt using the version_compare function, built in to PHP since 4.1:

php > print_r(version_compare("2.5.1",  "2.5.2")); // expect -1 -1 php > print_r(version_compare("2.5.2",  "2.5.2")); // expect 0 0 php > print_r(version_compare("2.5.5",  "2.5.2")); // expect 1 1 php > print_r(version_compare("2.5.11", "2.5.2")); // expect 1 1 

It seems PHP already works as you expect. If you are encountering different behavior, perhaps you should specify this.

Answer 2

Also, you can use the PHP built-in function as below by passing an extra argument to the version_compare()

if(version_compare('2.5.2', '2.5.1', '>')) {  print "First arg is greater than second arg"; } 

Please see version_compare for further queries.