如果带或（||）参数的语句不适用于in_array方法

Question

I have this snippet of code

public function dynamicSlugAction(Request $request, $slug)
{
    $array1 = ["coffee", "milk", "chocolate", "coca-cola"];
    $array2 = ["water", "juice", "tomato-juice", "ice-tea"];
    if (!in_array($slug, $array1) || !in_array($slug, $array2)) {
        throw new \Exception("The var " . strtoupper($slug) . " is not exist with parameter (slug): " . $slug);
    }
}

Even if I write a right value wich exist in array1 or array2 I have the error launched by the throw new \\Exception .

If I remove the or clause in the if statement and I write a right value, no error occured but I can't check the second condition.

Where am I wrong in my if statement?

Answer 1

You need to use logical and (&&) not or. You are saying

If $slug isn't in array1 or isn't in array 2, throw the exception. So to not throw the exception the slug value would need to be in BOTH array 1 and array 2.

What you really want (I assume), if that if the value of slug isn't in either array throw the exception, but if it exists in one of the arrays, do nothing and carry on. So change your if statement to:

if (!in_array($slug, $array1) && !in_array($slug, $array2)) {
  throw new \Exception("The var ".strtoupper($slug)." is not exist with parameter (slug): ".$slug);
}

Answer 2

When you wanna check,if 2 conditions are true then use the logical operator of and(&&).The or operator(||) is to check if either one is true.Just have in mind the Boolean Algebra in order not to lose track.

Or:

statment1=true;
statment2=false;
if(statment1=true||statment2=true){do stuff}//it will run because at least one statment is true

And:

statment1=true;
statment2=false;
if(statment1=true && statment2=true){do stuff}//it wont run because both statments must be true.

Answer 3

if (!in_array($slug, $array1) || !in_array($slug, $array2))

This condition will throw exception if value does not exists in one of arrays. So if your value exists in one array but not in the other, exception will be thrown.

Check out this logical disjunction table on wikipedia: https://en.wikipedia.org/wiki/Truth_table#Logical_disjunction_.28OR.29

Answer 4

You must use and operator:

public function dynamicSlugAction(Request $request, $slug)
{
    $array1 = ["coffee", "milk", "chocolate", "coca-cola"];
    $array2 = ["water", "juice", "tomato-juice", "ice-tea"];
    if (!in_array($slug, $array1) and !in_array($slug, $array2)) {
      throw new \Exception("The var ".strtoupper($slug)." is not exist with parameter (slug): ".$slug);
    }
}

Answer 5

如果您的意思是如果$slug存在于任何数组中，那么您不希望引发错误，则应使用&&

if (!in_array($slug, $array1) && !in_array($slug, $array2))