ISSET

Determine if a variable is declared and is different than NULL

SYNTAX


            isset ( mixed $var [, mixed $... ] ) : bool

PARAMETERS

var

The variable to be checked.

...

Another variable ...

RETURN

Returns TRUE if var exists and has any value other than NULL. FALSE otherwise.

EXAMPLES

1


            string(0) ""

            bool(true)

2


            NULL

            bool(false)

            

            bool(false)

            bool(true)

            

            bool(true)

            bool(true)

            

            int(-9223372036854775808)

            bool(true)

            

            int(9223372036854775807)

            bool(true)

            

            int(0)

            bool(true)

            

            int(1)

            bool(true)

            

            int(23)

            bool(true)

            

            int(0)

            bool(true)

            

            int(0)

            bool(true)

            

            int(-1)

            bool(true)

            

            int(1)

            bool(true)

            

            int(-23)

            bool(true)

            

            int(23)

            bool(true)

            

            int(0)

            bool(true)

            

            int(1)

            bool(true)

            

            int(19)

            bool(true)

            

            int(0)

            bool(true)

            

            int(1)

            bool(true)

            

            int(35)

            bool(true)

            

            float(0)

            bool(true)

            

            float(1.1)

            bool(true)

            

            float(23.45)

            bool(true)

            

            float(0)

            bool(true)

            

            float(10000000000)

            bool(true)

            

            float(230000000000)

            bool(true)

            

            string(0) ""

            bool(true)

            

            string(1) "0"

            bool(true)

            

            string(1) "1"

            bool(true)

            

            string(2) "23"

            bool(true)

            

            string(2) "-0"

            bool(true)

            

            string(2) "+0"

            bool(true)

            

            string(2) "-1"

            bool(true)

            

            string(2) "+1"

            bool(true)

            

            string(3) "-23"

            bool(true)

            

            string(3) "+23"

            bool(true)

            

            string(2) "00"

            bool(true)

            

            string(2) "01"

            bool(true)

            

            string(3) "023"

            bool(true)

            

            string(3) "0x0"

            bool(true)

            

            string(3) "0x1"

            bool(true)

            

            string(4) "0x23"

            bool(true)

            

            string(3) "0.0"

            bool(true)

            

            string(3) "1.1"

            bool(true)

            

            string(5) "23.45"

            bool(true)

            

            string(4) "0e10"

            bool(true)

            

            string(4) "1e10"

            bool(true)

            

            string(5) "23e10"

            bool(true)

            

            string(4) "0abc"

            bool(true)

            

            string(4) "1abc"

            bool(true)

            

            string(5) "23abc"

            bool(true)

            

            string(5) "-0abc"

            bool(true)

            

            string(5) "+0abc"

            bool(true)

            

            string(5) "-1abc"

            bool(true)

            

            string(5) "+1abc"

            bool(true)

            

            string(6) "-23abc"

            bool(true)

            

            string(6) "+23abc"

            bool(true)

            

            string(5) "00abc"

            bool(true)

            

            string(5) "01abc"

            bool(true)

            

            string(6) "023abc"

            bool(true)

            

            string(6) "0x0abc"

            bool(true)

            

            string(6) "0x1abc"

            bool(true)

            

            string(7) "0x23abc"

            bool(true)

            

            string(6) "0.0abc"

            bool(true)

            

            string(6) "1.1abc"

            bool(true)

            

            string(8) "23.45abc"

            bool(true)

            

            string(7) "0e10abc"

            bool(true)

            

            string(7) "1e10abc"

            bool(true)

            

            string(8) "23e10abc"

            bool(true)

            

            string(3) "abc"

            bool(true)

            

            string(4) "abc0"

            bool(true)

            

            string(4) "abc1"

            bool(true)

            

            string(5) "abc23"

            bool(true)

            

            string(5) "abc-0"

            bool(true)

            

            string(5) "abc+0"

            bool(true)

            

            string(5) "abc-1"

            bool(true)

            

            string(5) "abc+1"

            bool(true)

            

            string(6) "abc-23"

            bool(true)

            

            string(6) "abc+23"

            bool(true)

            

            string(5) "abc00"

            bool(true)

            

            string(5) "abc01"

            bool(true)

            

            string(6) "abc023"

            bool(true)

            

            string(6) "abc0x0"

            bool(true)

            

            string(6) "abc0x1"

            bool(true)

            

            string(7) "abc0x23"

            bool(true)

            

            string(6) "abc0.0"

            bool(true)

            

            string(6) "abc1.1"

            bool(true)

            

            string(8) "abc23.45"

            bool(true)

            

            string(7) "abc0e10"

            bool(true)

            

            string(7) "abc1e10"

            bool(true)

            

            string(8) "abc23e10"

            bool(true)

            

            array(0) {

            }

            bool(true)

            

            array(2) {

              [0]=>

              int(0)

              [1]=>

              int(1)

            }

            bool(true)

            

            object(stdClass)#1 (0) {

            }

            bool(true)

3


            int(1)


            bool(true)


            


            NULL


            bool(false)

4


            int(1)


            int(2)


            bool(true)


            


            NULL


            int(2)


            bool(false)

5


            bool(true)

            bool(false)

            bool(false)

6


            bool(true)

            bool(true)

            bool(false)

            bool(false)

            bool(false)

            bool(false)

7


            bool(true)

            bool(true)

            bool(true)

            bool(false)

            bool(false)

            bool(false)

LINKS

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