Artefacto's answer will also convert a 5.0 float number into a 5 integer. If that is bugging you like it was bugging me, I offer the answer of automatic type conversion via the multiplication operator:
If either operand is a float, then both operands are evaluated as floats, and the result will be a float. Otherwise, the operands will be interpreted as ints, and the result will also be an int.
$demo = array[
1, 2, 3, '1', '2', '3',
1.0, 2.1, 3.2, '1.0', '2.1', '3.2',
-17, '-17',
-1.0, -2.2, '-1.0', '-2.2',
0, '0', -0, '-0',
0.0, '0.0', -0.0, '-0.0',
];
foreach [$demo as $k => $v] {
if [is_numeric[$v] && is_string[$v]] {
$demo[$k] = 1 * $v;
}
}
echo ""; var_dump[$demo]; echo "
";
array[26] {
[0]=>
int[1]
[1]=>
int[2]
[2]=>
int[3]
[3]=>
int[1]
[4]=>
int[2]
[5]=>
int[3]
[6]=>
float[1]
[7]=>
float[2.1]
[8]=>
float[3.2]
[9]=>
float[1]
[10]=>
float[2.1]
[11]=>
float[3.2]
[12]=>
int[-17]
[13]=>
int[-17]
[14]=>
float[-1]
[15]=>
float[-2.2]
[16]=>
float[-1]
[17]=>
float[-2.2]
[18]=>
int[0]
[19]=>
int[0]
[20]=>
int[0]
[21]=>
int[0]
[22]=>
float[0]
[23]=>
float[0]
[24]=>
float[-0]
[25]=>
float[-0]
}
[PHP 4, PHP 5, PHP 7, PHP 8]
is_int — Find whether the type of a variable is integer
Description
is_int[mixed $value]: bool
Note:
To test if a variable is a number or a numeric string [such as form input, which is always a string], you must use is_numeric[].
Parameters
valueThe variable being evaluated.
Return Values
Returns
true if value is an int, false otherwise.
Examples
Example #1 is_int[] example
The above example will output:
is_int[23] = bool[true] is_int['23'] = bool[false] is_int[23.5] = bool[false] is_int['23.5'] = bool[false] is_int[NULL] = bool[false] is_int[true] = bool[false] is_int[false] = bool[false]
See Also
- is_bool[] - Finds out whether a variable is a boolean
- is_float[] - Finds whether the type of a variable is float
- is_numeric[] - Finds whether a variable is a number or a numeric string
- is_string[] - Find whether the type of a variable is string
- is_array[] - Finds whether a variable is an array
- is_object[] - Finds whether a variable is an object
Simon Neaves ¶
14 years ago
I've found that both that is_int and ctype_digit don't behave quite as I'd expect, so I made a simple function called isInteger which does. I hope somebody finds it useful.
Robin ¶
12 years ago
Keep in mind that is_int[] operates in signed fashion, not unsigned, and is limited to the word size of the environment php is running in.
In a 32-bit environment:
In a 64-bit environment:
If you find yourself deployed in a 32-bit environment where you are required to deal with numeric confirmation of integers [and integers only] potentially breaching the 32-bit span, you can combine is_int[] with is_float[] to guarantee a cover of the full, signed 64-bit span:
e dot sand at elisand dot com ¶
13 years ago
Simon Neaves was close on explaining why his function is perfect choice for testing for an int [as possibly most people would need]. He made some errors on his ctype_digit[] output though - possibly a typo, or maybe a bug in his version of PHP at the time.
The correct output for parts of his examples should be:
As you can see, the reason why using *just* ctype_digit[] may not always work is because it only returns TRUE when given a string as input - given a number value and it returns FALSE [which may be unexpected].
andre dot roesti at 7flex dot net ¶
12 years ago
With this function you can check if every of multiple variables are int. This is a little more comfortable than writing 'is_int' for every variable you've got.
davide dot renzi at gmail dot com ¶
6 years ago
I've found a faster way of determining an integer.
On my env, this method takes about half the time of using is_int[].
Cast the value then check if it is identical to the original.
petepostma at gmail dot spam dot com ¶
10 years ago
There is a versa to the vice of this int only type check.
is_int[ $integer_type] will only return true, if the TYPE is int, not the value
ctype_digit[ $string_type] will only return true if the TYPE is string, and its value is INT
therefore:
return [ is_int[$value] || ctype_digit[$value] ];
nicolas dot giraud at actiane dot com ¶
10 years ago
Just a shorter way to check if your variable is an int or a string containing a int without others digit than 0 to 9 :