Home php教程 PHP源码 php in_array,trim,isset,unset,is_numeric函数用法。

php in_array,trim,isset,unset,is_numeric函数用法。

Jun 08, 2016 pm 05:29 PM
array isset null unset

php in_array,trim,isset,unset,is_numeric函数用法。

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下面我们一一看讲一下这些函数的使用教程吧。

in_array($array)

这个函数是判断当前值是否为数组哦

EX:

$array= array(1,2);
if( in_array( $array ) )
{
 die('in_array判断它是数组');
}
echo '不是数组';

result:

in_array判断它是数组


trim($value)


trim函数是去除参数的空值包括null," "

isset($value)

isset是判断变量是否存在

unset($value)

销毁变量

下面我们来看看isset,unset实例吧。

$a = 'v';

isset( $a ) ? $a:NULL;

unset( $a );

isset( $a ) ? $a:NULL;

结果是:

v

Null

is_numeric($num)

$num =3;

if( is_numeric($num) )
{
 echo $num;
}
else
{
 echo '不是数值';
}

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