douhua1890 2016-06-30 16:23
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具有多种条件的三元运算符

Hello I am trying to properly format ternary operator to be using multiple conditions in php:

$result = ($var !== 1 || $var !== 2) ? '' : 'default';

The problem is that in this format I always get not true even iv the $var is 1 or 2. With one condition for example $var == 0 it is working fine. Any help will be welcome.

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  • dongwubao4785 2016-06-30 16:26
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    This statement will always be true:

    ($var !== 1 || $var !== 2)
    

    Because $var can never simultaneously be both values, it will always not be at least one of the two values. Which satisfies the || operator.

    If you want to know whether $var is one of the two values:

    ($var === 1 || $var === 2)
    

    If you want to know if $var is neither of the two values, you can negate the condition:

    (!($var === 1 || $var === 2))
    

    Or individually negate the operators in the condition and use && instead of || (since all conditions need to be met to prove the negative, instead of just one condition to prove the positive):

    ($var !== 1 && $var !== 2)
    

    Depending on readability and personal preference.

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