如何检查函数是否有值[重复]

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How do you create optional arguments in php? 6 answers

你如何在PHP中创建可选参数? 6个答案

I am not sure if the title is correct, my problem is that I have a class and functions inside it, I would like to check if the value for the function is set and if not set other value

我不确定标题是否正确,我的问题是我有一个类和函数,我想检查函数的值是否设置,如果没有设置其他值

class some_class
{
    private $width;

    function width( $value )
    {
        // Set another default value if this is not set
        $this->width = $value;
    }
}

$v = new some_class();


// Set the value here but if I choose to leave this out I want a default value
$v->width( 150 );

3 个解决方案

#1

This might be what you're looking for

这可能是你正在寻找的

class some_class
{
    function width($width = 100)
    {
        echo $width;
    }
}

$sc = new some_class();

$sc->width();
// Outputs 100

$sc->width(150);
// Outputs 150

#2

You can do something like this:

你可以这样做:

class SomeClass
{
    private $width;

    function setWidth($value = 100)
    {
        $this->width = $value;
    }
}

$object = new SomeClass();
$object->setWidth();
echo '<pre>';
print_r($object);

Will result into like this if empty:

如果为空则会产生这样的结果:

SomeClass Object
(
    [width:SomeClass:private] => 100
)

or something like this too:

或类似的东西:

class SomeClass
{
    private $width;

    function setWidth()
    {
        $this->width = (func_num_args() > 0) ? func_get_arg(0) : 100;
    }
}

$object = new SomeClass();
$object->setWidth();
echo '<pre>';
print_r($object); // same output

#3

Try this

class some_class
{
    private $width;
    function width( $value=500 )  //Give default value here
    {
        $this->width = $value; 
    }
}

Check Manual for default value.

检查手动的默认值。

#1