Php if var is numeric

PHP: is_numeric() function

The is_numeric() function is used to check whether a variable is numeric or not.

*Mixed : Mixed indicates that a parameter may accept multiple (but not necessarily all) types.

Return value:

TRUE if var_name is a number or a numeric string, FALSE otherwise.

Value Type: Boolean.

" ; > else < echo "$var_name1 is not Numeric. 
" ; > if (is_numeric($var_name2)) < echo "$var_name2 is Numeric.
" ; > else < echo "$var_name2 is not Numeric.
" ; > $result=is_numeric($var_name3); echo "[ $var_name3 is numeric? ]" .var_dump($result)."
"; $result=is_numeric($var_name4); echo "[ $var_name4 is numeric? ]" .var_dump($result)."
"; $result=is_numeric($var_name5); echo "[ $var_name5 is numeric? ]" .var_dump($result)."
"; $result=is_numeric($var_name6); echo "[ $var_name6 is numeric? ]" .var_dump($result)."
"; $result=is_numeric($var_name7); echo "[ $var_name7 is numeric? ]" .var_dump($result); ?> 

678 is Numeric. a678 is not Numeric. bool(true) [ 678 is numeric? ] bool(false) [ W3resource.com is numeric? ] bool(true) [ 698.99 is numeric? ] bool(false) [ Array is numeric? ] bool(true) [ 125689.66 is numeric? ]

Practice here online :

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Источник

is_numeric

Determines if the given variable is a number or a numeric string.

Parameters

The variable being evaluated.

Return Values

Returns true if value is a number or a numeric string, false otherwise.

Changelog

Version	Description
8.0.0	Numeric strings ending with whitespace ( «42 » ) will now return true . Previously, false was returned instead.

Examples

Example #1 is_numeric() examples

$tests = array(
«42» ,
1337 ,
0x539 ,
02471 ,
0b10100111001 ,
1337e0 ,
«0x539» ,
«02471» ,
«0b10100111001» ,
«1337e0» ,
«not numeric» ,
array(),
9.1 ,
null ,
» ,
);

foreach ( $tests as $element ) if ( is_numeric ( $element )) echo var_export ( $element , true ) . » is numeric» , PHP_EOL ;
> else echo var_export ( $element , true ) . » is NOT numeric» , PHP_EOL ;
>
>
?>

The above example will output:

'42' is numeric 1337 is numeric 1337 is numeric 1337 is numeric 1337 is numeric 1337.0 is numeric '0x539' is NOT numeric '02471' is numeric '0b10100111001' is NOT numeric '1337e0' is numeric 'not numeric' is NOT numeric array ( ) is NOT numeric 9.1 is numeric NULL is NOT numeric '' is NOT numeric

Example #2 is_numeric() with whitespace

$tests = [
» 42″ ,
«42 » ,
«\u9001» , // non-breaking space
«9001\u» , // non-breaking space
];

foreach ( $tests as $element ) if ( is_numeric ( $element )) echo var_export ( $element , true ) . » is numeric» , PHP_EOL ;
> else echo var_export ( $element , true ) . » is NOT numeric» , PHP_EOL ;
>
>
?>

Output of the above example in PHP 8:

' 42' is numeric '42 ' is numeric ' 9001' is NOT numeric '9001 ' is NOT numeric

Output of the above example in PHP 7:

' 42' is numeric '42 ' is NOT numeric ' 9001' is NOT numeric '9001 ' is NOT numeric

See Also

• Numeric strings
• ctype_digit() — Check for numeric character(s)
• is_bool() — Finds out whether a variable is a boolean
• is_null() — Finds whether a variable is null
• is_float() — Finds whether the type of a variable is float
• is_int() — Find whether the type of a variable is integer
• is_string() — Find whether the type of a variable is string
• is_object() — Finds whether a variable is an object
• is_array() — Finds whether a variable is an array
• filter_var() — Filters a variable with a specified filter

User Contributed Notes 8 notes

Note that the function accepts extremely big numbers and correctly evaluates them.

$v = is_numeric ( ‘58635272821786587286382824657568871098287278276543219876543’ ) ? true : false ;

var_dump ( $v );
?>

The above script will output:

So this function is not intimidated by super-big numbers. I hope this helps someone.

PS: Also note that if you write is_numeric (45thg), this will generate a parse error (since the parameter is not enclosed between apostrophes or double quotes). Keep this in mind when you use this function.

for strings, it return true only if float number has a dot

is_numeric( ‘42.1’ )//true
is_numeric( ‘42,1’ )//false

Apparently NAN (Not A Number) is a number for the sake of is_numeric().

echo «is » ;
if (! is_numeric ( NAN ))
echo «not » ;
echo «a number» ;
?>

Outputs «is a number». So something that is NOT a number (by defintion) is a number.

is_numeric fails on the hex values greater than LONG_MAX, so having a large hex value parsed through is_numeric would result in FALSE being returned even though the value is a valid hex number

is incorrect for PHP8, it’s numeric.

Note that this function is not appropriate to check if «is_numeric» for very long strings. In fact, everything passed to this function is converted to long and then to a double. Anything greater than approximately 1.8e308 is too large for a double, so it becomes infinity, i.e. FALSE. What that means is that, for each string with more than 308 characters, is_numeric() will return FALSE, even if all chars are digits.

However, this behaviour is platform-specific.

In such a case, it is suitable to use regular expressions:

function is_numeric_big($s=0) return preg_match(‘/^-?\d+$/’, $s);
>

Note that is_numeric() will evaluate to false for number strings using decimal commas.

regarding the global vs. american numeral notations, it should be noted that at least in japanese, numbers aren’t grouped with an extra symbol every three digits, but rather every four digits (for example 1,0000 instead of 10.000). also nadim’s regexen are slightly suboptimal at one point having an unescaped ‘.’ operator, and the whole thing could easily be combined into a single regex (speed and all).

$eng_or_world = preg_match
( ‘/^[+-]?’ . // start marker and sign prefix
‘((((6+)|(7(,7)+)))?(\\.4)?(5*)|’ . // american
‘(((8+)|(8(\\.3)+)))?(,3)?(9*))’ . // world
‘(e8+)?’ . // exponent
‘$/’ , // end marker
$str ) == 1 ;
?>

i’m sure this still isn’t optimal, but it should also cover japanese-style numerals and it fixed a couple of other issues with the other regexen. it also allows for an exponent suffix, the pre-decimal digits are optional and it enforces using either grouped or ungrouped integer parts. should be easier to trim to your liking too.

Источник

is_int

Finds whether the type of the given variable is integer.

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

The variable being evaluated.

Return Values

Returns true if value is an int , false otherwise.

Examples

Example #1 is_int() example

$values = array( 23 , «23» , 23.5 , «23.5» , null , true , false );
foreach ( $values as $value ) echo «is_int(» ;
var_export ( $value );
echo «) color: #007700″>;
var_dump ( is_int ( $value ));
>
?>

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

User Contributed Notes 30 notes

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.

function isInteger ( $input ) return( ctype_digit ( strval ( $input )));
>

var_dump ( is_int ( 23 )); //bool(true)
var_dump ( is_int ( «23» )); //bool(false)
var_dump ( is_int ( 23.5 )); //bool(false)
var_dump ( is_int ( NULL )); //bool(false)
var_dump ( is_int ( «» )); //bool(false)

var_dump ( ctype_digit ( 23 )); //bool(true)
var_dump ( ctype_digit ( «23» )); //bool(false)
var_dump ( ctype_digit ( 23.5 )); //bool(false)
var_dump ( ctype_digit ( NULL )); //bool(false)
var_dump ( ctype_digit ( «» )); //bool(true)

var_dump ( isInteger ( 23 )); //bool(true)
var_dump ( isInteger ( «23» )); //bool(true)
var_dump ( isInteger ( 23.5 )); //bool(false)
var_dump ( isInteger ( NULL )); //bool(false)
var_dump ( isInteger ( «» )); //bool(false)
?>

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.

is_int ( 2147483647 ); // true
is_int ( 2147483648 ); // false
is_int ( 9223372036854775807 ); // false
is_int ( 9223372036854775808 ); // false
?>

In a 64-bit environment:

is_int ( 2147483647 ); // true
is_int ( 2147483648 ); // true
is_int ( 9223372036854775807 ); // true
is_int ( 9223372036854775808 ); // false
?>

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:

$small = 2147483647 ; // will always be true for is_int(), but never for is_float()
$big = 9223372036854775807 ; // will only be true for is_int() in a 64-bit environment

if( is_int ( $small ) || is_float ( $small ) ); // passes in a 32-bit environment
if( is_int ( $big ) || is_float ( $big ) ); // passes in a 32-bit environment
?>

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:

var_dump ( ctype_digit ( 23 )); //bool(false)
var_dump ( ctype_digit ( «23» )); //bool(true)
var_dump ( ctype_digit ( 23.5 )); //bool(false)
var_dump ( ctype_digit ( NULL )); //bool(false)
var_dump ( ctype_digit ( «» )); //bool(false)
?>

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).

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.

function are_int ( ) $args = func_get_args ();
foreach ( $args as $arg )
if ( ! is_int ( $arg ) )
return false ;
return true ;
>

// Example:
are_int ( 4 , 9 ); // true
are_int ( 22 , 08, ‘foo’ ); // false
?>

Источник

PHP is_numeric() Function

Check whether a variable is a number or a numeric string, or not:

$b = 0;
echo «b is » . is_numeric($b) . «
«;

$c = 32.5;
echo «c is » . is_numeric($c) . «
«;

$d = «32»;
echo «d is » . is_numeric($d) . «
«;

$e = true;
echo «e is » . is_numeric($e) . «
«;

$f = null;
echo «f is » . is_numeric($f) . «
«;
?>

Definition and Usage

The is_numeric() function checks whether a variable is a number or a numeric string.

This function returns true (1) if the variable is a number or a numeric string, otherwise it returns false/nothing.

Syntax

Parameter Values

Technical Details

Return Value:	TRUE if variable is a number or a numeric string, FALSE otherwise
Return Type:	Boolean
PHP Version:	4.0+

❮ PHP Variable Handling Reference

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