PHP/Language Basics/Php Functions

Functions to Check Data Type

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Name Description is_null() Returns true if the value is null (no type) is_string() Returns true if the value is a string is_int() Returns true if the value is an integer is_float() Returns true if the value is a floating-point value is_array() Returns true if the value is an array is_object() Returns true if the value is an object is_a() Deprecated; checks if an object is a specified class instanceof() Checks if an object is an instance of a class

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Functions to Convert Data Types

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Function Description

doubleval() Accepts a value and returns double equivalent

intval() Accepts a value and returns integer equivalent

strval() Accepts a value and returns string equivalent

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Functions to Test Data Types

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Function Description

is_array() Returns true if the argument is an array

is_bool() Returns true if the argument is boolean

is_double() Returns true if the argument is a double

is_int() Returns true if the argument is an integer

is_object() Returns true if the argument is an object

is_string() Returns true if the argument is a string

is_null() Returns true if the argument is null

is_resource() Returns true if the argument is a resource

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GMP Functions

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Name Description gmp_abs Calculates absolute value gmp_add Adds numbers gmp_and Logical and gmp_clrbit Clears bit gmp_cmp Compares numbers gmp_com Calculates one"s complement gmp_div_q Divides numbers gmp_div_qr Divides numbers and gets quotient and remainder gmp_div_r Remainder of the division of numbers gmp_div Alias of gmp_div_q() gmp_divexact Exact division of numbers gmp_fact Factorial gmp_gcd Calculates GCD gmp_gcdext Calculates GCD and multipliers gmp_hamdist Hamming distance gmp_init Creates GMP number gmp_intval Converts GMP number to integer gmp_invert Inverse by modulo gmp_jacobi Jacobi symbol gmp_legendre Legendre symbol gmp_mod Modulo operation gmp_mul Multiplies numbers gmp_neg Negates number gmp_or Logical or gmp_perfect_square Perfect square check gmp_popcount Population count gmp_pow Raises number into power gmp_powm Raises number into power with modulo gmp_prob_prime Checks if number is "probably prime" gmp_random Random number gmp_scan0 Scans for 0 gmp_scan1 Scans for 1 gmp_setbit Sets bit gmp_sign Sign of number gmp_sqrt Calculates square root gmp_sqrtrem Square root with remainder gmp_strval Converts GMP number to string gmp_sub Subtracts numbers gmp_xor Logical xor

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Using the @ operator to suppress a warning about the undefined variables

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<?php $scores = array(88, 75, 91, 84); list($maths, , $history) = $scores;

@printf("

Maths: %d; English: %d; History: %d; Biology: %d.

\n",

$maths, $english, $history, $biology); ?>

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