How to display array in php

With the continuous development of Internet technology, PHP has become one of the most popular Web programming languages. In PHP, arrays are an important data structure that can store multiple values ​​and can be expanded and reduced dynamically. During the development process, we often need to use PHP to operate arrays, but how can we display arrays effectively? Next, this article will introduce you to several methods on how to display arrays in PHP.

Method 1: Use the print_r function

In PHP, the print_r function can print out an array. This function will print out all elements in the array, including key names and key values. For example, the following code can output an array to the browser:

$arr = array("apple", "banana", "pear");
print_r($arr);

The output result is:

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

As can be seen from the above results, the array has three elements, namely apple, banana and pear. This method is relatively simple and suitable for smaller array output.

Method 2: Use the var_dump function

In PHP, the var_dump function can output the type and value of a variable to the browser, including array types. Unlike the print_r function, the var_dump function can also output the data type and length of each element. For example, the following code can output an array to the browser:

$arr = array("apple", "banana", "pear");
var_dump($arr);

The output result is:

array(3) {
  [0]=>
  string(5) "apple"
  [1]=>
  string(6) "banana"
  [2]=>
  string(4) "pear"
}

As can be seen from the above results, the array has three elements, namely apple, For banana and pear, the data type of each element is a string, with lengths of 5, 6 and 4 respectively. This method is more detailed and suitable for debugging and analyzing arrays.

Method 3: Use foreach loop

In PHP, you can use foreach loop to traverse all elements of the array and output the key and value of each element. This method is more flexible and can output data in any format as needed. For example, the following code can output an array into HTML format:

$arr = array("姓名"=>"张三", "年龄"=>20, "性别"=>"男");
echo "";
foreach ($arr as $key => $value) {
    echo "";
}
echo "
".$key."
".$value."
";

The output result is:

As can be seen from the above results, the array has three elements, namely name, age and gender. When using a foreach loop to output, the array elements can be converted into a table format to make the data clearer and easier to read.

Method 4: Use the json_encode function

In PHP, you can use the json_encode function to encode an array into a JSON string and output it to the browser. JSON (JavaScript Object Notation) is a lightweight data exchange format that has the advantages of good readability, easy transmission, and easy parsing. For example, the following code can output an array as a JSON string:

$arr = array("apple", "banana", "pear");
echo json_encode($arr);

The output result is:

["apple","banana","pear"]

As can be seen from the above results, the array is converted into JSON string format. Using this method, you can easily pass array data to a JavaScript program for processing.

Summary

This article introduces four ways to output arrays in PHP: using the print_r function, using the var_dump function, using the foreach loop, and using the json_encode function. Each of these methods has advantages and disadvantages, and the appropriate method can be selected according to the specific scenario. I hope this article can provide some reference for PHP developers.

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