一种更简单的在php中编码的方法“if（$ x == $ a [1] || $ x == $ a [2] || $ x == $ a [3] ......）

Question

As the title states, whats a more simple way to do

if ( $somevariable == $somearray[1] || $somevariable  == $somearray[3] || $somevariable  == $somearray[10] ) 

Seems like even with 3 variables.. there would be a shortcut.

I know this doesnt work, but something like would be nice:

if ($somevariable == $somearray[1],$somearray[3],$somearray[10]) {

Answer 1

一种选择

if ( in_array( $somevariable, array( $somearray[1], $somearray[3], $somearray[10] ) ) {}

Answer 2

你可以使用in_array 。

Answer 3

In fact, your code is already all right.
If you don't want to dive into depths of refactoring , just leave it as is. Because:

• it does exactly what it's intended for - checks some variable against some conditions.
• more important: it looks like the code to check some variable against some conditions. So, you could always tell what does it do. That's way more important than some fancy shortland.

In pursue for conciseness, you should not forget readability .
The only solution acceptable is one which no less readable than your current one. Which reads (literally: if you read it aloud) like it's intentded.
Example: by making such a function,

function whateverCondition($variable,$array) {
  return ( $variable == $array[1] 
        || $variable  == $array[3] 
        || $variable  == $array[10]); 
}

you can call it later this way,

if (whateverCondition($somevariable,$somearray))

keeping both conciseness and readability (if you name it properly).

As it was mentioned in comments, parameters seems a bit redundant. it depends. if it's going to be a function, keep them in place.
if this function going to be a method of some appropriate class - you can omit them, making it

if ($user->meetCondition())

Answer 4

Another option using array_intersect_key() :

if (in_array($var, array_intersect_key($somearray, array_flip(array(1, 3, 10)))))
{
}

This is mostly useful if you have a large numbers of indexes to check.

---

In a variadic function, as @knittl suggested:

function in_array_keys($needle, $haystack)
{
    $keys = array_flip(array_slice(func_get_args(), 2);
    return in_array($needle, array_intersect_key($haystack, $keys)));
}

var_dump(in_array_keys($var, $somearray, 1, 2, 3));