缺少array_hash（）函数。 无法创建数组的哈希值

Intro:

I need a function that can take an array and return a hash of it.

This should similar to spl_object_hash(), except that it returns a hash for given array.

So, far I've tried

function array_hash(array $array) {

   return spl_object_hash((object) $array); 
}

The problems

1) This algorithm isn't efficient by itself. For example, what if I pass something like this:

  $array = array(
     'foo' => 'bar',
     'bool' => false,
     'junk' => array(
         'junk1' => array('foo' => array('__test__'))
      )
  )

It won't cast nested arrays to objects.

2) Another major problem is that, spl_object_hash() returns a different hash for the same object on each new HTTP request.

The question

Again: I need a persistent hash for an array. Unlike spl_object_hash(), the will be persistent on each HTTP request. How can I do this correctly?

How about serializing the array first?

md5(serialize($array));

The above answer by Martin works fine but what I do:

function array_signature($arr, $sort=true)
{
    // Sorting helps generating a similar fingerprint for similar arrays
    if($sort) {
        array_multisort($arr);
    }

    // MD5 seems to be the fastest hashing function -- we don't care about collision for this
    // JSON seems faster than serialize()
    return md5(json_encode($arr));
}

Calling array_multisort() first ensures that, for associative arrays, the same signature is returned for:

• ['a'=>1, 'b'=>2]
• ['b'=>2, 'a'=>1]

Benchmarks seem to agree: md5() is the fastest hashing function in PHP. It has a lot of potential security issues so should not be used for hashing passwords, but for an array signature this should not be an issue.

Similarly, json_encode() is the fastest encoding algorithm in PHP (faster than serialize())