How to process arrays in php

PHP is a very excellent programming language that has excellent performance in processing data. When it comes to processing arrays, PHP also provides a wealth of functions and syntax to simplify programmers' work. This article will introduce how to process arrays in PHP.

1. Create an array

In PHP, we can create an array in two ways: one is to use the array() function, and the other is to use the [] symbol.

The syntax format of using the array() function to create an array is as follows:

$数组名 = array(元素1, 元素2, 元素3, ...);

For example:

$weekdays = array('Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday');

We can also use the [] symbol to create an array. The syntax format of this method is as follows:

$数组名 = [元素1, 元素2, 元素3, ...];

For example:

$fruits = ['apple', 'banana', 'orange', 'pear'];

The advantage of using an array is that we can store multiple data in one variable and process these data at any time.

2. Access array elements

In PHP, we can use the array name and index number to access array elements. The index number is the number of each element in the array, counting from 0. For example, to access the second element "Tuesday" in the $weekdays array, we can use the following code:

echo $weekdays[1];

The output is "Tuesday".

3. Array operation

PHP provides a large number of array operation functions. The following are some common array operation functions:

1. array_push(): to the end of the array Add one or more elements.

$fruits = array('apple', 'banana', 'orange', 'pear');
array_push($fruits, 'grape', 'watermelon');
print_r($fruits);

The output result is:

Array
(
    [0] => apple
    [1] => banana
    [2] => orange
    [3] => pear
    [4] => grape
    [5] => watermelon
)

2. array_pop(): Delete an element from the end of the array.

$fruits = array('apple', 'banana', 'orange', 'pear');
array_pop($fruits);
print_r($fruits);

The output result is:

Array
(
    [0] => apple
    [1] => banana
    [2] => orange
)

3. array_shift(): Delete an element from the beginning of the array.

$fruits = array('apple', 'banana', 'orange', 'pear');
array_shift($fruits);
print_r($fruits);

The output result is:

Array
(
    [0] => banana
    [1] => orange
    [2] => pear
)

4. array_unshift(): Add one or more elements to the beginning of the array.

$fruits = array('apple', 'banana', 'orange', 'pear');
array_unshift($fruits, 'grape', 'watermelon');
print_r($fruits);

The output result is:

Array
(
    [0] => grape
    [1] => watermelon
    [2] => apple
    [3] => banana
    [4] => orange
    [5] => pear
)

5. array_slice(): intercept some elements in the array.

$fruits = array('apple', 'banana', 'orange', 'pear', 'grape');
$sliced_fruits = array_slice($fruits, 1, 3);
print_r($sliced_fruits);

The output result is:

Array
(
    [0] => banana
    [1] => orange
    [2] => pear
)

The first parameter is the array that needs to be intercepted, the second parameter is the starting position of interception (counting from 0), and the The three parameters are the length of interception.

4. Traverse the array

You can use for loop, foreach loop and while loop to traverse the array. Among them, the use of foreach loop is the most common. The following is an example of using a foreach loop to traverse an array:

$fruits = array('apple', 'banana', 'orange', 'pear', 'grape');
foreach ($fruits as $fruit) {
    echo $fruit . ' ';
}

The output result is:

apple banana orange pear grape

In the foreach statement, $fruits represents the array that needs to be traversed, and $fruit represents the currently traversed element. We can also output both the keys and values ​​of the array elements. The sample code is as follows:

$fruits = array('apple', 'banana', 'orange', 'pear', 'grape');
foreach ($fruits as $key => $value) {
    echo $key . '=>' . $value . ' ';
}

The output result is:

0=>apple 1=>banana 2=>orange 3=>pear 4=>grape

5. Summary

Through the above introduction, I believe everyone Gained a deeper understanding of array operations in PHP. As an important data type, arrays are frequently used in programs. Mastering its related operating functions and syntax has a positive effect on improving development efficiency.

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