不管什么类型 如果是数字，就返回数字，如果不是数字就返回0
在PHP中用$_GET['id']的时候就可以这样来一个转换...太好了
PHP代码
- $id = intval($_GET['id']);
intval
(PHP 4, PHP 5)
intval — Get the integer value of a variable
Description
int
intval
(
mixed
$var
[, int
$base= 10
] )
Returns the integer value of
var
,
using the specified
base
for the conversion
(the default is base 10).
Parameters
-
var
-
The scalar value being converted to an integer
-
base
-
The base for the conversion (default is base 10)
Return Values
The integer value of
var
on success, or 0 on
failure. Empty arrays and objects return 0, non-empty arrays and
objects return 1.
The maximum value depends on the system. 32 bit systems have a
maximum signed integer range of -2147483648 to 2147483647. So for example
on such a system, intval('1000000000000') will return
2147483647. The maximum signed integer value for 64 bit systems is
9223372036854775807.
Strings will most likely return 0 although this depends on the
leftmost characters of the string. The common rules of
integer casting
apply.
<?php
echo intval(42); // 42
echo intval(4.2); // 4
echo intval('42'); // 42
echo intval('+42'); // 42
echo intval('-42'); // -42
echo intval(042); // 34
echo intval('042'); // 42
echo intval(1e10); // 1410065408
echo intval('1e10'); // 1
echo intval(0x1A); // 26
echo intval(42000000); // 42000000
echo intval(420000000000000000000); // 0
echo intval('420000000000000000000'); // 2147483647
echo intval(42, 8); // 42
echo intval('42', 8); // 34
?>