Use PHP arrays to implement common scenarios

Use PHP arrays to implement common scenarios

PHP is a popular open source programming language that is widely used in the development of web applications and websites. One of the important features is array (Array), through which large amounts of data can be stored and manipulated. This article will introduce how to use PHP arrays to implement common scenarios, including array creation, traversal, and manipulation.

1. Creation of array
   Create an array, which can be declared manually using the array() function or square brackets []. For example:

// 使用 array() 函数创建数组
$fruits = array('apple', 'banana', 'orange');

// 使用方括号 [] 手动声明数组
$numbers = [1, 2, 3, 4, 5];

The keys and values ​​of the array can be of any type, including strings, numbers, Boolean values, objects, etc.

2. Traversal of arrays
   Traversing arrays is one of the basic methods of operating arrays. PHP provides a variety of methods for traversing arrays.

a. Use for loop
Use for loop to traverse numeric index array, for example:

$fruits = array('apple', 'banana', 'orange');
for ($i = 0; $i < count($fruits); $i++) {
    echo $fruits[$i] . '<br>';
}

b. Use foreach loop
Use foreach loop to traverse associative array and numeric index array, for example:

$person = array('name' => '张三', 'age' => 18);
foreach ($person as $key => $value) {
    echo $key . ': ' . $value . '<br>';
}

c. Use while loop and each() function
Use while loop and each() function to traverse associative array, for example:

$person = array('name' => '张三', 'age' => 18);
reset($person);
while (list($key, $value) = each($person)) {
    echo $key . ': ' . $value . '<br>';
}

3. Array operations
   Operations on arrays include actions such as adding, deleting, modifying, and finding elements. PHP provides a variety of functions and methods to accomplish these operations.

a. Add elements
Use array_push(), array_unshift(), array_splice() and [] operators to add elements to the array, for example:

$fruits = array('apple', 'banana', 'orange');
array_push($fruits, 'strawberry');
array_unshift($fruits, 'peach');
array_splice($fruits, 2, 0, 'grape');
$fruits[] = 'kiwi';

b . Delete elements
Use unset(), array_pop(), array_shift() and array_splice() to delete elements in the array, for example:

$fruits = array('apple', 'banana', 'orange', 'grape', 'kiwi');
unset($fruits[1]);
array_pop($fruits);
array_shift($fruits);
array_splice($fruits, 1, 2);

c. Modify elements
Use the [] operator and array_splice() can modify the elements in the array, for example:

$fruits = array('apple', 'banana', 'orange', 'grape', 'kiwi');
$fruits[1] = 'pear';
array_splice($fruits, 3, 1, 'mango');

d. Find elements
Use in_array(), array_search(), array_keys() and array_values() to find elements in the array, For example:

$fruits = array('apple', 'banana', 'orange', 'grape', 'kiwi');
if (in_array('orange', $fruits)) {
    echo '找到了橙子！';
}
$key = array_search('apple', $fruits);
echo '苹果的索引是：' . $key;
$keys = array_keys($fruits);
$values = array_values($fruits);

In summary, this article introduces how to use PHP arrays to implement common scenarios, including the creation, traversal and operation of arrays. Mastering these basic skills will make you more comfortable in PHP development.

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