New function in PHP8: new application method of array_key_first()

With the release of PHP8, new functions also come. Among them, array_key_first() has appeared in PHP7.3, but it has a new application method in PHP8. Let us take a look at it together.

The definition of array_key_first()

First, let’s take a look at the definition of array_key_first(). Its function is to return the first key name in the array, or null if the array is empty.

Syntax: array_key_first($array);

Parameters:
$array: required. Need to return the array of the first key name.

Return value:
Returns the first key name of the given array. If the array is empty, returns null.

New application method of array_key_first()

In PHP8, the application method of array_key_first() has been extended to a wider range of scenarios. In previous usage methods, we usually use a foreach loop to find the first key name of the array:

foreach($arr as $key => $value){
  break;
}
echo $key;

Now, we can use array_key_first() to simplify this process:

$key = array_key_first($arr);
echo $key;

This This method is not only more concise, but also faster, because it does not need to traverse the entire array, but only needs to return the first key name.

Cases of array_key_first() in practical applications

In order to better understand the application method of array_key_first(), we can look at some practical cases. For example:

1. Find the first key name in the array

$arr = array('a'=>1, 'b'=>2, 'c'=>3);
echo array_key_first($arr);
//输出结果：a

2. Traverse the first element in the array

$arr = array('a'=>1, 'b'=>2, 'c'=>3);
$key = array_key_first($arr);
echo $arr[$key];
//输出结果：1

3. Determine whether the array is empty

$arr = array();
if(array_key_first($arr) !== null){
  echo "数组非空";
} else {
  echo "数组为空";
}
//输出结果：数组为空

Summary

array_key_first() is one of the new functions in PHP8, and its application method has been extended to a wider range of scenarios. Its function is to return the first key name in the array, or null if the array is empty. Using array_key_first() can simplify the process of finding the first key name in the array, and can also help us determine whether the array is empty faster. In practical applications, we need to use array_key_first() reasonably to make our code more concise and efficient.

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