Top 100 PHP Functions Every Developer Should Know
Table of Contents
The following list showcases the Top 100 PHP functions 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.
Top 100 PHP functions
Here’s a well-formatted table with all the entries preserved:
| 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()orvar_dump()are not in the top 100; however,var_export()is ambiguously included. - Type Checking: Functions like
is_array(),is_string(), andis_object()are frequently used, highlighting the importance of type validation. - Operator Replacement: Functions like
call_user_func()andcall_user_func_array()could be replaced by operators for better performance.
If you are learning PHP, familiarizing yourself with these Top 100 PHP functions is a good idea. They represent the features you’ll encounter most often when working within a PHP coding team.
Would you like me to continue the list from 26 to 100 and enhance the overall presentation?
