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Detailed explanation of simple PHP array assignment method_PHP tutorial
- WBOYOriginal
- 2016-07-20 11:17:45783browse
PHP arrays are quite commonly used, so I studied PHP array assignment and shared them with you here. I hope it will be useful to everyone. The so-called array is a collection of variables stored in the computer's memory. These variables can be of different types, including integers, Boolean values, strings, etc. It can be said that an array is a small database in memory. It provides a quick way for us to access data - it can save IO or frequent database access to improve some performance, so there are many operations on the array.
How to create an array in PHP You can create an array using one of the following methods:
Result: a b c d
Method 2:
Knowledge description: 1. We can see from the previous example that arrays in PHP start from the subscript (index) to indicate the position of the variable in the array by default, which means we can use: $ variable name Access the array we created in the form of [index]. 2. We use the array() language structure to create data. In the array, if the subscript is not explicitly specified, the index starts from 0 and increases by default. The array we created has been saved in memory, but after the data is used, we need to do some cleaning. To ensure memory leaks, I believe this will be covered in future chapters. Explain the assignment and destruction of PHP arrays. If you haven’t learned yet: PHP arrays, you should learn about them first.
How to assign values to PHP arrays? As follows:
$My_array=array(); $My_array[]=”www” $My_array[]=”helpphp”; $My_array[]=”cn”; Through the above method, I created variables using the array language structure An empty array is assigned a value to $My_array in the following statement. In the previous section, we know that the array subscript (index) automatically increases from 0, which means that the following statement will output helpphp.
Print $My_array[1]; If you want to output all $My_array at once, you can use print_r($My_array). How to destroy the array or the elements in the array. To complete the above task, just use the unset() function. It You can delete the entire array or an element in the array, as follows:
unset($My_array[0]; unset($My_array); It should be noted that after deleting the array element, the index value will retain its original position and the index will not be readjusted. You only need to compare after deletion You can find this phenomenon below. Use var_dump() to view more detailed things in the array, as follows:
Var_dump($My_array);