Internal PHP function usage: revisited

Warning: This blogpost has been posted over two years ago. That is a long time in development-world! The story here may not be relevant, complete or secure. Code might not be complete or obsoleted, and even my current vision might have (completely) changed on the subject. So please do read further, but use it with caution.
Posted on 05 Aug 2014
Tagged with: [ PHP

A small update on the blogpost about PHP’s internal function usages:

A lot of people are asking about functions like isset, empty, print, echo etc, as they are not present in the current result list. The thing is, is that these are not really functions, but language constructs. This means that PHP treats them a bit different than normal functions, and this results sometimes in seemingly “strange” behaviour when trying to use them like regular functions:


will not work, while the following does:


In any case, I’ve revisited the results a bit, and added some of these constructs to the list: echo, empty, eval, isset, print, unset and even yield. As with the first attempt, I’ve taken some of the peaks out of the equation: every repository with over 1000 of the same functions: =>  define - 7000 =>  empty - 5824 =>  count - 5052 =>  isset - 16320 =>  sprintf - 5948 =>  isset - 5225 =>  class_exists - 35648 =>  define - 74004

So without these, the new results, the top 22:

86937	isset
43159	echo
31697	empty
29252	substr
26146	count
24248	is_array
22572	strlen
19365	sprintf
18090	unset
16584	str_replace
15462	strpos
15241	preg_match
14630	in_array
14305	chr
13218	trim
12747	implode
12534	explode
11853	array_merge
11850	define
11495	strtolower
10079	is_string

The rest of the results can be found here.

Some interesting facts:

  • isset() is winning by a landslide. There are in the almost 1000 repositories checked, twice as much calls to isset() than to the number two function (echo).
  • After some fine-tuning and tweaking, the top-3 are all language construct, the first “real” function substr() is #4, and count() #5. These two have swapped places from the last check because of some repositories with a unreasonable high number of count() statements.
  • echo (#2) is used more than print (#42) with a ratio of almost 5:1.
  • In order, the most calls are made to: is_array, is_string, is_null, is_object, is_numeric, is_bool, is_callable, is_resource, is_scalar, is_a, is_integer, is_double, is_long.
  • 529 times eval() is called :(
  • 71 times a generator is generated with yield.