How to convert the traversed data into an array in php

In PHP, it is often necessary to process data returned from a database or other data sources. Sometimes, the data is not returned in the form of an array, but in other formats, such as json, string, etc. In this case, we need to convert this data into a PHP array to perform data operations. So how to achieve this? Next, let’s talk about the method of converting data in PHP into an array through traversal.

In PHP, there are two very commonly used data types, one is an array and the other is an object. In practice, we often need to convert objects into arrays, or convert data in other formats into arrays. At this time, a convenient way is to use the traversal method to take out the data one by one and save it into the array.

First, we need to know how to traverse data in PHP. In PHP, there are several different ways to traverse:

1. for loop

for ($i = 0; $i < count($arr); $i++) {
    // 对元素进行操作
}

2. foreach loop

foreach ($arr as $value) {
    // 对元素进行操作
}

3. while loop

while ($row = mysqli_fetch_assoc($result)) {
    // 对元素进行操作
}

The above three loop methods each have their own advantages and disadvantages. In actual use, it is necessary to choose the appropriate method according to the specific situation.

Next, we use an example to illustrate how to convert data in PHP into an array through traversal.

Suppose we have the following array:

$data = array(
    array('id' => 1, 'name' => 'Tom', 'age' => 20),
    array('id' => 2, 'name' => 'Jerry', 'age' => 22),
    array('id' => 3, 'name' => 'Kate', 'age' => 25),
);

We want to convert it into the following array:

$new_data = array(
    array('id' => 1, 'name' => 'Tom', 'age' => 20),
    array('id' => 2, 'name' => 'Jerry', 'age' => 22)
);

We only want to retain the elements whose id is less than or equal to 2, and save the result as a new array.

The specific implementation steps are as follows:

1. Define a new array to save the filtered elements.

$new_data = array();

2. Traverse all elements in the original array.

foreach ($data as $value) {
    // 对元素进行操作
}

3. Determine whether the id of the current element is less than or equal to 2, and if so, save it to a new array.

if ($value['id'] <= 2) {
    $new_data[] = $value;
}

4. The final $new_data array is the result we need.

Complete code:

$data = array(
    array('id' => 1, 'name' => 'Tom', 'age' => 20),
    array('id' => 2, 'name' => 'Jerry', 'age' => 22),
    array('id' => 3, 'name' => 'Kate', 'age' => 25),
);

$new_data = array();

foreach ($data as $value) {
    if ($value['id'] <= 2) {
        $new_data[] = $value;
    }
}

print_r($new_data);

The output result is:

Array
(
    [0] => Array
        (
            [id] => 1
            [name] => Tom
            [age] => 20
        )

    [1] => Array
        (
            [id] => 2
            [name] => Jerry
            [age] => 22
        )

)

In this way, we have achieved the purpose of converting data in PHP into an array through traversal.

Summary:

In PHP, converting data into an array through traversal is a very common operation. Through the above examples, we can see that implementing this function is very simple, just follow the steps. At the same time, different data sources may require different traversal methods, and we need to choose according to the specific situation. In data operations, the operation of converting data into an array is more of a coding habit, which can improve the readability and maintainability of the code. I hope this article can help you learn and understand PHP's array operations.

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