What are the several ways to traverse a one-dimensional array in php

How PHP traverses a one-dimensional array: 1. Use the for loop method, and the loop variable $i starts from 0 until the array length is -1; 2. Use the foreach loop method to assign values ​​to the variable $ through the loop. value, and then use the variable $value to access each element; 3. Use the while loop method to calculate the length of the array, and then use a loop variable $i to traverse the array; 4. Use the do-while loop to calculate the length of the array, Then use a loop variable $i to iterate through the array.

The operating environment of this tutorial: windows10 system, php8.1.3 version, DELL G3 computer.

php is a widely used programming language that is widely used in web development. In PHP, traversing one-dimensional arrays is also a very common operation. This article will introduce how to traverse one-dimensional arrays.

Definition of one-dimensional array

In PHP, a one-dimensional array is a data structure containing a set of elements, each element has an associated key value. One-dimensional arrays can be defined using array() or [], for example:

$array = array('apple', 'banana', 'grape', 'orange'); // 使用array()定义
$array = ['apple', 'banana', 'grape', 'orange']; // 使用[]定义

The above code defines a one-dimensional array named $array, which contains 4 elements: 'apple', 'banana ', 'grape' and 'orange'.

Use a for loop to traverse a one-dimensional array

The first way to traverse a one-dimensional array is to use a for loop. The specific implementation is as follows:

for ($i = 0; $i < count($array); $i++) {
    echo $array[$i] . &#39;<br />&#39;;
}

In this code, a for loop is used to traverse the array. The loop variable $i starts from 0 and goes to the array length -1. Inside the loop, each element is accessed using array subscripts and their values ​​are output.

Use a foreach loop to traverse a one-dimensional array

The second way to traverse a one-dimensional array is to use a foreach loop. The specific implementation is as follows:

foreach ($array as $value) {
    echo $value . &#39;<br />&#39;;
}

In this code, a foreach loop is used to traverse the array. The loop will take out one element from the array each time and assign it to the variable $value. Then inside the loop body, use the variable $value to access each element and output their value.

Use a while loop to traverse a one-dimensional array

The third way to traverse a one-dimensional array is to use a while loop. The specific implementation is as follows:

$count = count($array);
$i = 0;
 
while ($i < $count) {
    echo $array[$i] . &#39;<br />&#39;;
    $i++;
}

In this code, first calculate the length of the array, and then use a loop variable $i to traverse the array. Each time it loops, the element with index $i in the array is output, and the loop variable $i is incremented by 1. When the loop variable $i is equal to the length of the array, exit the loop.

Use a do-while loop to traverse a one-dimensional array

The fourth way to traverse a one-dimensional array is to use a do-while loop. The specific implementation is as follows:

$count = count($array);
$i = 0;
 
do {
    echo $array[$i] . &#39;<br />&#39;;
    $i++;
} while ($i < $count);

In this code, like the while loop, the length of the array is first calculated. Then use a loop variable $i to traverse the array, output the element with index $i in the array each time it loops, and add 1 to the loop variable $i. When the loop variable $i is equal to the length of the array, exit the loop.

Summary

The above introduces four methods of traversing one-dimensional arrays in PHP, which are using for loop, foreach loop, while loop and do-while loop. These methods are widely used in actual development, and developers can choose different methods to traverse one-dimensional arrays according to their needs. In addition, it is also important to note that when traversing an array, you must pay attention to the range of the array subscript to avoid the array going out of bounds.

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