is_numeric
(PHP 4, PHP 5, PHP 7, PHP 8)
is_numeric — 检测变量是否为数字或数字字符串
参数
-
value
-
需要检测的变量。
返回值
如果 value
是数字或数字字符串,
返回 true
;否则返回 false
。
范例
示例 #1 is_numeric() 示例
<?php
$tests = array(
"42",
1337,
0x539,
02471,
0b10100111001,
1337e0,
"0x539",
"02471",
"0b10100111001",
"1337e0",
"not numeric",
array(),
9.1,
null,
'',
);
foreach ($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;
}
}
?>
以上例程会输出:
'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
参见
- 数字字符串
- ctype_digit() - 做纯数字检测
- is_bool() - 检测变量是否是布尔值
- is_null() - 检测变量是否为 null
- is_float() - 检测变量是否是浮点型
- is_int() - 检测变量是否是整数
- is_string() - 检测变量是否是字符串
- is_object() - 检测变量是否是一个对象
- is_array() - 检测变量是否是数组