douxiuyu2028 2014-05-14 20:58
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if($ variable)和if(isset($ variable))之间的区别

What is the difference between something like this:

if(isset($variable)) { 

  do_something(); 

}

and this

if($variable) { 

  do_something(); 

}

I want to say that the first case, isset checks to see if the variable exists and is not null. But what if it's set to an empty array?

In the second case, I want to say that if the variable has been instantiated at all, it will pass as true.

Thank you for any future clarification.

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3条回答 默认 最新

  • drpmazn9021 2014-05-14 21:01
    关注
    if(isset($variable))
    

    checks if the variable exists and is set (different from NULL).

    if($variable)
    

    just checks what boolean the variable sends back, in this case its like

    if($variable === true)
    
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