PHP - Getting the index of a element from a array

问题

How can I get the current element number when I'm traversing a array?

I know about count(), but I was hoping there's a built-in function for getting the current field index too, without having to add a extra counter variable.

like this:

foreach($array as $key => value)
  if(index($key) == count($array) ....

回答1:

You should use the key() function.

key($array)

should return the current key.

If you need the position of the current key:

array_search($key, array_keys($array));

回答2:

PHP arrays are both integer-indexed and string-indexed. You can even mix them:

array('red', 'green', 'white', 'color3'=>'blue', 3=>'yellow');

What do you want the index to be for the value 'blue'? Is it 3? But that's actually the index of the value 'yellow', so that would be an ambiguity.

Another solution for you is to coerce the array to an integer-indexed list of values.

foreach (array_values($array) as $i => $value) {
  echo "$i: $value\n";
}

Output:

0: red
1: green
2: white
3: blue
4: yellow

回答3:

foreach() {
    $i++;
    if(index($key) == $i){}
    //
}

回答4:

function Index($index) {
    $Count = count($YOUR_ARRAY);
    if ($index <= $Count) {
        $Keys = array_keys($YOUR_ARRAY);
        $Value = array_values($YOUR_ARRAY);
        return $Keys[$index] . ' = ' . $Value[$index];
    } else {
        return "Out of the ring";
    }
}

echo 'Index : ' . Index(0);

Replace the ( $YOUR_ARRAY )

回答5:

an array does not contain index when elements are associative. An array in php can contain mixed values like this:

$var = array("apple", "banana", "foo" => "grape", "carrot", "bar" => "donkey");   
print_r($var);

Gives you:

Array
(
    [0] => apple
    [1] => banana
    [foo] => grape
    [2] => carrot
    [bar] => donkey
)

What are you trying to achieve since you need the index value in an associative array?

回答6:

There is no way to get a position which you really want.
For associative array, to determine last iteration you can use already mentioned counter variable, or determine last item's key first:

end($array);
$last = key($array);
foreach($array as $key => value)
  if($key == $last) ....

来源：https://stackoverflow.com/questions/3764654/php-getting-the-index-of-a-element-from-a-array

标签

php

arrays

field