How to retain the first few characters of a php array

In PHP, for strings, we can use the substr function to intercept the characters at the specified position, but for the elements in the array, how to retain the first few characters?

Next, let’s introduce how to retain the first few characters of a PHP array.

1. Use the array_map function

Using the array_map function can perform the same operation on each element in the array, so we can use the array_map function to intercept each element in the array. Specifies the length of characters.

Code example:

<?php $arr = array("apple", "banana", "orange", "watermelon");

function cut_string($str, $max_len)
{
    return substr($str, 0, $max_len);
}

$new_arr = array_map(function($item) {
    return cut_string($item, 3);
}, $arr);

print_r($new_arr);  //输出结果：Array ( [0] => app [1] => ban [2] => ora [3] => wat )
?>

In the above code, we first define an array $arr, and then define a function cut_string to intercept the string. Next, we use the array_map function to intercept each element in the array $arr, and save the intercepted results in the new array $new_arr.

Judging from the results, we have successfully retained the first three characters of each element in the original array.

2. Use the array_walk function

Use the array_walk function to modify each element in the array, and it can also be used to intercept characters of a specified length.

Code example:

<?php $arr = array("apple", "banana", "orange", "watermelon");

function cut_string(&$value, $key, $max_len)
{
    $value = substr($value, 0, $max_len);
}

array_walk($arr, "cut_string", 3);

print_r($arr);  //输出结果：Array ( [0] => app [1] => ban [2] => ora [3] => wat )
?>

In the above code, we also define an array $arr. Then, we defined a function cut_string, using a reference in the form of &$value to modify each element. Next, we use the array_walk function to execute the cut_string function on each element in the array $arr, cutting the element into characters of the specified length.

Judging from the results, we have also successfully retained the first three characters of each element in the original array.

3. Use foreach loop

If you think the above two functions are a bit complicated, then we can also use foreach loop to retain the first few characters of the array.

Code example:

<?php $arr = array("apple", "banana", "orange", "watermelon");

foreach ($arr as &$value) {
    $value = substr($value, 0, 3);
}

print_r($arr);  //输出结果：Array ( [0] => app [1] => ban [2] => ora [3] => wat )
?>

In the above code, we also define an array $arr. Then, use a foreach loop to intercept each element in the array $arr, and save the modified elements in the original array $arr.

Judging from the results, we have also successfully retained the first three characters of each element in the original array.

Conclusion

In PHP, it is not difficult to retain the first few characters of the elements in the array. We can use the array_map function, array_walk function or foreach loop to achieve it. Through the above three methods, you can choose which method to use according to your actual needs.

Of course, if you like a simpler method, you can choose to use a foreach loop, because this method is the most intuitive and simple and does not require additional definition of functions.

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