PHP Functions Essential Reference

Overview

PHP’s variable-related functions are a key part of the language. Skilled programmers rely on them extensively to build robust code that uses type-checking. Functions like var_dump() and print_r() are also invaluable when debugging.

Here is a quick, task-based overview of the function group:

• Cast a value from one type to another: doubleval(), intval(), strval()

• Set the type of a variable: settype()

• Determine the type of a variable: is_array(), is_bool(), is_double(), is_float(), is_int(), is_integer(), is_long(), is_null(), is_numeric(), is_object(), is_real(), is_resource(), is_scalar(), is_string(), get_resource_type(), gettype()

• Destroy variables: unset()

• Gather information about variables: empty(), get_defined_vars(), isset(), print_r() ...