How to deduplicate php array without retaining key values

In PHP programming, we often need to perform deduplication operations on arrays in order to extract the only elements in the array. PHP provides a variety of deduplication methods, one of the more commonly used is to use the array_unique() function for deduplication. However, a shortcoming of this function is that it cannot retain the original key values ​​of the array and can only return a new array with duplicate elements removed. If we need to retain the original key values, we need to use other methods.

The following introduces a method of using the array_flip() function, which uses the value of the array as the key, then deduplicates the key, and finally returns an array of values ​​without keys.

<?php     //定义一个数组，包含重复和非重复元素
    $arr = array("a", "b", "c", "a", "d", "e", "b");
    var_dump($arr);

    $arr = array_flip($arr);
    $arr = array_keys($arr);
    var_dump($arr);
?>

In the above code, an array $arr is first defined, which contains repeated and non-repeating elements. Then use the array_flip() function to interchange the key values ​​of the array, that is, use the value of the array element as the key.

Then use the array_keys() function to get all the keys, that is, the unique elements in the original array, and then get the new array $arr2.

Finally, use the var_dump() function to view the elements of the new array $arr2, and you will see the array that has been deduplicated and has no key values.

It should be noted that this method only applies to arrays whose values ​​are strings or numbers. For arrays whose values ​​are complex types such as objects and arrays, other methods need to be used for deduplication.

In short, no matter which method is used for array deduplication, we need to first analyze the characteristics and element types of the array, and then choose a suitable method for deduplication.

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