is_double
As celelibi at gmail dot com stated, is_float checks ONLY the type of the variable not the data it holds!
If you want to check if string represent a floating point value use the following regular expression and not is_float(),
or poorly written custom functions.
/^[+-]?(([0-9]+)|([0-9]*\.[0-9]+|[0-9]+\.[0-9]*)|
(([0-9]+|([0-9]*\.[0-9]+|[0-9]+\.[0-9]*))[eE][+-]?[0-9]+))$/
is_float
(PHP 4, PHP 5)
is_float — 检测变量是否是浮点型
描述
bool is_float
( mixed $var
)
如果 var 是 float 则返回 TRUE，否则返回 FALSE。
Note: 若想测试一个变量是否是数字或数字字符串（如表单输入，它们通常为字符串），必须使用 is_numeric()。
参见 is_bool()、is_int()、is_integer()、is_numeric()、is_string()、is_array() 和 is_object()。
add a note
User Contributed Notesis_float
kshegunov at gmail dot com
01-Apr-2008 05:32
01-Apr-2008 05:32
celelibi at gmail dot com
04-Mar-2008 12:31
04-Mar-2008 12:31
Unlike others comment may let you think, this function tests *only* the type of the variable. It does not perform any other test.
If you want to check if a string represents a valid float value, please use is_numeric instead.
WHITE new media architects - Jeroen
10-Jan-2008 07:24
10-Jan-2008 07:24
The above printed "is_true_float" function is not correct.
It gives wrong answers on the following tests:
is_true_float("-4,123"); # returns false
is_true_float("0,123"); # returns false
So I changed the function to correctly handle qouted negative floats and quoted floats near zero:
<?php
function is_true_float($mVal)
{
return ( is_float($mVal)
|| ( (float) $mVal != round($mVal)
|| strlen($mVal) != strlen( (int) $mVal) )
&& $mVal != 0 );
}
?>
Kenaniah Cerny
07-Nov-2007 03:21
07-Nov-2007 03:21
For those of you who have discovered that is_float() does not behave exactly the way you would expect it to when passing a string, here is a function that extends is_float properly report floating numbers given any sort of mixed variable.
<?php
function is_true_float($val){
if( is_float($val) || ( (float) $val > (int) $val || strlen($val) != strlen( (int) $val) ) && (int) $val != 0 ) return true;
else return false;
}
?>
<?php
//Tests
'4.0' returns true
'2.1' returns true
0 returns false
"0" returns false
3. returns true
13 returns false
"12" returns false
3.53 returns true
?>
Enjoy
phper
26-Jan-2006 04:08
26-Jan-2006 04:08
A better way to check for a certain number of decimal places is to use :
$num_dec_places = 2;
number_format($value,$num_dec_places);
kirti dot contact at gmail dot com
19-Oct-2005 02:18
19-Oct-2005 02:18
To check a float only should contain certain number of decimal places, I have used this simple function below
<?
function is_deccount($number,$decimal=2){
$m_factor=pow(10,$decimal);
if((int)($number*$m_factor)==$number*$m_factor)
return true;
else
return false;
}
?>