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In PHP programming, we often use arrays to store data. In the process of processing arrays, array_fill and array_fill_keys are two very commonly used functions. Although they have some similar functions, they have some significant differences in use and are suitable for different scenarios. Understanding the difference between the two and choosing the right function in the right scenario can help us write more efficient and maintainable code.
The array_fill function is used to fill an array. The content of the fill is the specified value. The index of the array is generated continuously starting from a certain starting value. This function is especially suitable for you to generate an array of specified lengths and all elements are the same value.
grammar :
array_fill(int $start_index, int $num, mixed $value): array
$start_index : The starting index of the array.
$num : The number of elements of the array.
$value : The value of the array padding.
Example :
$filledArray = array_fill(0, 5, 'PHP');
print_r($filledArray);
Output :
Array
(
[0] => PHP
[1] => PHP
[2] => PHP
[3] => PHP
[4] => PHP
)
In this example, array_fill creates an array of 5 elements, each with a value of 'PHP' and the index starts at 0.
The array_fill_keys function fills an array according to the specified key. It requires an array of keys and a value, and assigns the value to the array elements corresponding to these keys. This function is especially suitable for situations where you already have specific keys that need to be filled and want to assign the same value to these keys.
grammar :
array_fill_keys(array $keys, mixed $value): array
$keys : an array containing all keys.
$value : The value to assign to these keys.
Example :
$keys = ['a', 'b', 'c'];
$filledArray = array_fill_keys($keys, 'PHP');
print_r($filledArray);
Output :
Array
(
[a] => PHP
[b] => PHP
[c] => PHP
)
In this example, array_fill_keys uses the elements in the $keys array as the keys to the array and uses 'PHP' as the value corresponding to these keys.
Index and keys :
array_fill is used to generate arrays based on integer indexes.
array_fill_keys generates an array based on the specified key.
Different uses :
array_fill is suitable for you to create an array of specified length and indexes, and the array elements are the same value.
array_fill_keys works when you have a custom set of keys that you want to fill with the same values for.
Use array_fill : If you only care about the length of the array, and the elements of the array do not require specific key-value pairs, but only need each element to have the same value, then using array_fill is more appropriate.
For example, if you need an array with 10 'PHP's and the index starts at 0, array_fill is perfect.
Use array_fill_keys : If you already have a specific set of keys (probably strings, numbers, or other types) and you want all of these keys to be the same value, array_fill_keys is more appropriate.
For example, array_fill_keys is more convenient when you need to fill in the same default value for some specific configuration items or identifiers.
array_fill and array_fill_keys are both very useful functions when dealing with arrays, but they each work for different scenarios. Understanding their differences and choosing to use them in the right scenario can make our code more concise and efficient.
