PHP commonly used array functions (2)

* Stacks and queues are the two most commonly used data structures. As for what stacks and queues are, it is beyond the course requirements.

* All you need to know now is that stacks and queues can quickly add elements to both ends of an array. The addition and deletion operations can be done

* The stack operation of the array: the addition and deletion of elements are only allowed at one end of the array

* 1. The tail

* 1. array_push(array, value1[,value2...): Push to the stack, return the new array number

* 2. array_pop(array): Pop the last element from the stack, the array length is reduced by 1

* 2. Header

* 1. array_unshift(array,value1[,value2...): Push to the stack and return the number of new arrays

* 2. array_shift(array): Pop the stack, pop the first element at the head, and the array length is reduced by 1

* Queue operation of the array: the addition and deletion of elements are allowed at both ends

* 1. Enter the tail into the queue, Head dequeue

* 1. array_push(array, value1[,value2...):Enqueue, return the number of new arrays

* 2. array_shift(array):Dequeue, Pop the first element in the head, and the array length is reduced by 1

* 2. The head is added to the queue, and the tail is dequeued

* 1. array_unshift(array,value1[,value2...) :Enqueue, return the new array number

* 2. array_pop(array): Dequeue, pop the last element, the array length is reduced by 1

* Note:

* 1. Added elements always appear as index elements, and multiple

can be added at the same time. * 2. Deletion can only pop up one element at a time.

* 3. Addition and deletion operations will cause the array pointer to be The reset operation reset()

echo &#39;<pre class="brush:php;toolbar:false">&#39;;
$user = [&#39;id&#39;=>5,&#39;name&#39;=>&#39;peter&#39;,&#39;gender&#39;=>&#39;male&#39;,&#39;age&#39;=>30];
print_r($user); //查看数组
echo &#39;<hr color="red">&#39;;

//First, simulate the stack operation: addition and deletion of elements are only allowed at one end

//1. array_push(array, value1[,value2.. .): Push the tail onto the stack, return the new array number

echo array_push($user, &#39;php中文网&#39;,&#39;www.php.cn&#39;),&#39;<br>&#39;;
print_r($user); //查看新成的数组

//2. array_pop(array): Pop the tail off the stack, pop the last element, and reduce the array length by 1

echo array_pop($user),&#39;<br>&#39;;
print_r($user); //查看新成的数组

//Repeat An element is popped from the tail and has been restored to its original state

echo array_pop($user),&#39;<br>&#39;;
print_r($user); //查看新成的数组

//3. array_unshift(array, value1[, value2...): Push the head onto the stack and return the new array number

echo array_unshift($user, &#39;php中文网&#39;,&#39;www.php.cn&#39;),&#39;<br>&#39;;
print_r($user); //查看新成的数组

//4. array_shift(array): Pop the head from the stack, pop the first element of the head, and reduce the array length by 1

echo array_shift($user),&#39;<br>&#39;;
print_r($user); //查看新成的数组
echo array_shift($user),&#39;<br>&#39;;
print_r($user); //查看新成的数组

//Second: Simulate queue operation: additions and deletions must be done at both ends , not allowed to be completed at the same end

// 1. array_push(array, value1[,value2...): The tail is added to the queue and the new array number is returned

echo array_push($user, &#39;php中文网&#39;,&#39;www.php.cn&#39;),&#39;<br>&#39;;
print_r($user); //查看新成的数组

// 2. array_shift (array): The head is dequeued, the first element of the head is popped out, and the array length is reduced by 1

echo array_shift($user),&#39;<br>&#39;;  //出队的id=5这个元素,当然返回的只有值5
print_r($user); //查看新成的数组

// 3. array_unshift(array,value1[,value2...): The head is put into the queue, Return the number of new arrays

echo array_unshift($user, &#39;华为&#39;,&#39;小米&#39;),&#39;<br>&#39;;
print_r($user); //查看新成的数组

// 4. array_pop(array): dequeue the tail, pop the last element, and reduce the array length by 1

echo array_pop($user),&#39;<br>&#39;;
print_r($user); //查看新成的数组