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In the previous article "How to find the first non-repeating character in a given string through PHP", I introduced how to find the first non-repeating character in a given string through PHP. Non-repeating characters. Interested friends can learn about it~
So this article will introduce to you how to get the array of the first n elements. What does it mean?
Let's take a look at the specific problem description: How to write a PHP program to get an array in which n elements are removed from the beginning of the given array.
It doesn’t matter if you don’t understand it yet, let’s look at the code directly:
The PHP code is as follows:
<?php function take($items, $n = 1) { return array_slice($items, 0, $n); } var_dump(take([1, 2, 3], 1)); var_dump(take([1, 2, 3, 4, 5], 2));
The result of printing the obtained array is:
array (size=1) 0 => int 1 array (size=2) 0 => int 1 1 => int 2
Note:
PHP array_slice()
The function takes out a value in the array according to the conditions and returns it; the return value is the selection in the returned array fixed part. (If the array has string keys, the returned array will preserve the key names.)
array_slice()
The syntax of the function is "array_slice(array,start,length,preserve )
";
parameters respectively represent:
array必需,规定数组。 start必需,数值,规定取出元素的开始位置。 0 = 第一个元素。 ---如果该值设置为正数,则从前往后开始取。 ---如果该值设置为负数,则从后向前取 start 绝对值。 -2 意味着从数组的倒数第二个元素开始。 length可选,数值,规定被返回数组的长度。 ---如果该值设置为整数,则返回该数量的元素。 ---如果该值设置为负数,则函数将在举例数组末端这么远的地方终止取出。 ---如果该值未设置,则返回从 start 参数设置的位置开始直到数组末端的所有元素。 preserve可选,规定函数是保留键名还是重置键名。可能的值: ---true - 保留键名 ---false - 默认。重置键名
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