Top 100 PHP Functions Every Developer Should Know

Top 100 PHP Functions The following list showcases the 100 most commonly used native PHP functions. These functions are ranked from 1 to 100 based on their usage frequency across PHP code repositories. The reference corpus includes a list of 2,500 PHP Open Source projects (top 1,000 Composer packages, public repositories from GitHub/GitLab/Gitee, and downloaded archives). The analysis was conducted using the Exakat static analysis engine, version 2.4.7. The 'Average' column indicates how often a function is called within a single project. For instance, the count() function is used in 4 out of 5 projects and called approximately 61 times per project. It is both popular and heavily used. On the other hand, dirname() is commonly used but less frequently called (used by 56% of projects for about 13 usages). Clicking on the links will direct you to the documentation for each function. Additional insights are provided at the end of the list. The 100 Most Popular PHP Functions Rank Function Usage % Count 1 file_exists 66.05% 18 2 count 63.67% 87 3 str_replace 63.58% 51 4 implode 62.72% 48 5 substr 60.30% 70 6 array_merge 60.02% 51 7 sprintf 59.89% 103 8 dirname 58.91% 17 9 explode 58.30% 37 10 in_array 58.27% 49 11 strpos 58.08% 31 12 is_array 58.05% 73 13 strlen 56.37% 45 14 array_key_exists 54.87% 88 15 array_keys 54.72% 23 16 preg_match 52.02% 40 17 file_get_contents 51.76% 11 18 trim 48.49% 37 19 is_string 48.46% 27 20 array_values 48.46% 10 21 is_file 46.90% 7 22 method_exists 46.62% 11 23 array_map 46.11% 17 24 file_put_contents 46.11% 7 25 strtolower 45.44% 26 26 function_exists 44.97% 21 27 preg_replace 44.40% 23 28 defined 43.44% 27 29 is_dir 41.70% 8 30 json_decode 41.54% 10 31 json_encode 41.16% 15 32 call_user_func 41.06% 5 33 array_filter 41.00% 10 34 strtr 40.55% 6 35 fwrite 40.08% 7 36 rtrim 39.85% 8 37 strrpos 39.54% 4 38 call_user_func_array 39.41% 4 39 filter_var 39.25% 3 40 class_exists 39.22% 17 41 header 38.71% 11 42 array_flip 38.62% 3 43 realpath 38.11% 6 44 ini_get 38.01% 6 45 get_class 36.01% 14 46 is_object 35.03% 15 47 unlink 34.96% 8 48 trigger_error 34.84% 8 49 array_shift 34.71% 8 50 is_int 33.76% 7 51 spl_autoload_register 33.57% 1 52 is_numeric 32.93% 13 53 strtoupper 32.93% 9 54 mkdir 32.93% 4 55 array_pop 32.52% 7 56 ltrim 31.95% 5 57 headers_sent 31.95% 2 58 fopen 31.88% 8 59 array_unique 31.79% 6 60 str_repeat 31.47% 9 61 basename 31.25% 6 62 array_slice 30.39% 5 63 fclose 29.91% 7 64 time 29.47% 16 65 is_callable 29.37% 5 66 preg_match_all 29.28% 4 67 is_bool 29.15% 3 68 microtime 28.74% 5 69 spl_autoload_unregister 28.71% 1 70 var_export 28.61% 4 71 array_unshift 28.58% 3 72 max 28.42% 7 73 array_search 28.29% 4 74 apcu_fetch 28.29% 0 75 extension_loaded 28.20% 4 76 getcwd 28.17% 2 77 preg_split 28.14% 4 78 reset 28.10% 6 79 end 28.04% 4 80 gettype 28.04% 4 81 stream_resolve_include_path 27.85% 0 82 md5 27.72% 6 83 getenv 27.66% 6 84 apcu_add 27.41% 0 85 ucfirst 27.34% 7 86 ksort 27.31% 3 87 date 27.18% 14 88 is_null 26.90% 27 89 parse_url 26.61% 3 90 preg_quote 26.61% 4 91 array_reverse 26.58% 3 92 array_diff 26.45% 4 93 base64_encode 26.14% 4 94 version_compare 26.04% 4 95 preg_replace_callback 25.91% 4 96 current 25.25% 3 97 round 25.25% 7 98 min 25.15% 4 99 serialize 25.02% 6 Insights from the Top 100 PHP Functions Common Categories: Most commonly used functions are related to strings, arrays, and file handling. Math Functions: Not prominently ranked, as mathematical operations are often handled via operators. Database Functions: Functions like pdo, mysqli, pg_ are mostly handled via classes or components, hence not in the list. Deprecation: No recently deprecated functions appear in the top 100. Usage of Composer: Some native functions are used less frequently due to popular Composer packages replacing them. Crypto Functions: Only md5() appears widely; hash() is ranked 159th (not shown here). This needs improvement for better security practices. Debug Functions: Functions like print_r() or var_dump() are not in the top 100; however, var_export() is ambiguously included. Type Checking: Functions like is_array(), is_string(), and is_object() are frequently used, highlighting the importance of type validation. Operator Replacement: Functions like call_user_func() and call_user_func_array() could be replaced by operators for better performance. If you are learning PHP, familiarizing yourself with these 100 functions is a good idea. They represent the features you’ll encounter most often when working within a PHP coding team. Our Best Top 100 PHP functions in 2025 - Shikshatech Top 100 PHP functions in 2025 :

Mar 17, 2025 - 12:24

Top 100 PHP Functions

The following list showcases the 100 most commonly used native PHP functions. These functions are ranked from 1 to 100 based on their usage frequency across PHP code repositories. The reference corpus includes a list of 2,500 PHP Open Source projects (top 1,000 Composer packages, public repositories from GitHub/GitLab/Gitee, and downloaded archives). The analysis was conducted using the Exakat static analysis engine, version 2.4.7. The 'Average' column indicates how often a function is called within a single project.

For instance, the count() function is used in 4 out of 5 projects and called approximately 61 times per project. It is both popular and heavily used. On the other hand, dirname() is commonly used but less frequently called (used by 56% of projects for about 13 usages).

Clicking on the links will direct you to the documentation for each function. Additional insights are provided at the end of the list.

The 100 Most Popular PHP Functions

Rank	Function	Usage %	Count
1	file_exists	66.05%	18
2	count	63.67%	87
3	str_replace	63.58%	51
4	implode	62.72%	48
5	substr	60.30%	70
6	array_merge	60.02%	51
7	sprintf	59.89%	103
8	dirname	58.91%	17
9	explode	58.30%	37
10	in_array	58.27%	49
11	strpos	58.08%	31
12	is_array	58.05%	73
13	strlen	56.37%	45
14	array_key_exists	54.87%	88
15	array_keys	54.72%	23
16	preg_match	52.02%	40
17	file_get_contents	51.76%	11
18	trim	48.49%	37
19	is_string	48.46%	27
20	array_values	48.46%	10
21	is_file	46.90%	7
22	method_exists	46.62%	11
23	array_map	46.11%	17
24	file_put_contents	46.11%	7
25	strtolower	45.44%	26
26	function_exists	44.97%	21
27	preg_replace	44.40%	23
28	defined	43.44%	27
29	is_dir	41.70%	8
30	json_decode	41.54%	10
31	json_encode	41.16%	15
32	call_user_func	41.06%	5
33	array_filter	41.00%	10
34	strtr	40.55%	6
35	fwrite	40.08%	7
36	rtrim	39.85%	8
37	strrpos	39.54%	4
38	call_user_func_array	39.41%	4
39	filter_var	39.25%	3
40	class_exists	39.22%	17
41	header	38.71%	11
42	array_flip	38.62%	3
43	realpath	38.11%	6
44	ini_get	38.01%	6
45	get_class	36.01%	14
46	is_object	35.03%	15
47	unlink	34.96%	8
48	trigger_error	34.84%	8
49	array_shift	34.71%	8
50	is_int	33.76%	7
51	spl_autoload_register	33.57%	1
52	is_numeric	32.93%	13
53	strtoupper	32.93%	9
54	mkdir	32.93%	4
55	array_pop	32.52%	7
56	ltrim	31.95%	5
57	headers_sent	31.95%	2
58	fopen	31.88%	8
59	array_unique	31.79%	6
60	str_repeat	31.47%	9
61	basename	31.25%	6
62	array_slice	30.39%	5
63	fclose	29.91%	7
64	time	29.47%	16
65	is_callable	29.37%	5
66	preg_match_all	29.28%	4
67	is_bool	29.15%	3
68	microtime	28.74%	5
69	spl_autoload_unregister	28.71%	1
70	var_export	28.61%	4
71	array_unshift	28.58%	3
72	max	28.42%	7
73	array_search	28.29%	4
74	apcu_fetch	28.29%	0
75	extension_loaded	28.20%	4
76	getcwd	28.17%	2
77	preg_split	28.14%	4
78	reset	28.10%	6
79	end	28.04%	4
80	gettype	28.04%	4
81	stream_resolve_include_path	27.85%	0
82	md5	27.72%	6
83	getenv	27.66%	6
84	apcu_add	27.41%	0
85	ucfirst	27.34%	7
86	ksort	27.31%	3
87	date	27.18%	14
88	is_null	26.90%	27
89	parse_url	26.61%	3
90	preg_quote	26.61%	4
91	array_reverse	26.58%	3
92	array_diff	26.45%	4
93	base64_encode	26.14%	4
94	version_compare	26.04%	4
95	preg_replace_callback	25.91%	4
96	current	25.25%	3
97	round	25.25%	7
98	min	25.15%	4
99	serialize	25.02%	6

Insights from the Top 100 PHP Functions

Common Categories: Most commonly used functions are related to strings, arrays, and file handling.
Math Functions: Not prominently ranked, as mathematical operations are often handled via operators.
Database Functions: Functions like pdo, mysqli*, pg_* are mostly handled via classes or components, hence not in the list.
Deprecation: No recently deprecated functions appear in the top 100.
Usage of Composer: Some native functions are used less frequently due to popular Composer packages replacing them.
Crypto Functions: Only md5() appears widely; hash() is ranked 159th (not shown here). This needs improvement for better security practices.
Debug Functions: Functions like print_r() or var_dump() are not in the top 100; however, var_export() is ambiguously included.
Type Checking: Functions like is_array(), is_string(), and is_object() are frequently used, highlighting the importance of type validation.
Operator Replacement: Functions like call_user_func() and call_user_func_array() could be replaced by operators for better performance.

If you are learning PHP, familiarizing yourself with these 100 functions is a good idea. They represent the features you’ll encounter most often when working within a PHP coding team.

Our Best Top 100 PHP functions in 2025 - Shikshatech

Top 100 PHP functions in 2025 : the most frequently used PHP functions, which you are sure to meet in any decent code base

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