PHP多重逻辑运算符

Question

Trying to figure out the best way to do this. I have a PHP function that checks if something is true or not, and if it is, returns some JSON data.

The issue I'm having is that either one can return the data if the other is null, or both are true.

This is what I've tried:

if( $logic_type === true && $description== 'null' ){
    return json_encode( self::returnDataArray( $return_arrs ) );
}

if( $description === true && $logic_type == 'null' ){
    return json_encode( self::returnDataArray( $return_arrs ) );
}

if($description=== true && $logic_type === true ){
    return json_encode( self::returnDataArray( $return_arrs ) );
}

That seems to be way too long in the tooth. So I tried:

if( $logic_type === true && $description== 'null' || $description === true && $logic_type == 'null' || $description=== true && $logic_type === true ){
    return json_encode( self::returnDataArray( $return_arrs ) );
}

But that only works if the last condition is met.

Answer 1

You should use parentheses for grouping your conditions

Quote from Operator Precedence

Use of parentheses, even when not strictly necessary, can often increase readability of the code by making grouping explicit rather than relying on the implicit operator precedence and associativity.

Try

if( ($logic_type === true && $description== 'null') || ($description === true && $logic_type == 'null') || ($description=== true && $logic_type === true) ){

    return json_encode( self::returnDataArray( $return_arrs ) );

}

Answer 2

You have to enclose $logic_type === true && $description== 'null' ||.... in the brackets because you are using && and || . Use the code below

if( ($logic_type === true && $description== 'null') || ($description === true && $logic_type == 'null') || ($description=== true && $logic_type === true ))
{
    return json_encode( self::returnDataArray( $return_arrs ) );
}

Answer 3

This looks like the perfect example of using an exculsive or ( A XOR B ). Which means either A or B , but not both. In your case you want either $logic_type to be null, or $description to be null, but not both to be null. That or they both would be true. So we can simplify the expression to this, using a bit-wise XOR:

if( ($logic_type === 'null' ^ $description === 'null') || 
    ($logic_type === true && $description === true) )
{
    return json_encode( self::returnDataArray( $return_arrs ) );
}

Note that will only be if the only possible values for $logic_type and $description where either: true or 'null' .