Which function is used to output an array in php

php has two functions for outputting arrays: 1. print_r(). This function can output the contents and structure of the entire array, and will display the keys and elements in a certain format. The syntax is "print_r (array variable) "; 2. var_dump() can output the data content and structure of the entire array, and can output relevant information (type and value) of the array elements. When outputting the array, the array will recursively expand the values ​​and display its structure through indentation. Syntax "var_dump(array variable)".

The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer

In PHP, echo/print is generally used Output specific array unit values, and can also be used with a loop to output all array elements one by one.

But how to output the array at once? Which PHP function to use?

In fact, PHP has two built-in functions to output the contents and structure of the entire array:

• print_r()

• var_dump()

#Let’s talk about these two functions.

1. Use print_r() to output an array

The print_r() function is used to print variables in a more understandable form. Through print_r( ) function can output the contents and structure of the entire array, and will display the keys and elements according to a certain format.

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$arr=array("姓名"=>"张三","年龄"=>25,"性别"=>"男");
print_r($arr);
?>

Output result:

##One-dimensional array function, if it is a multi-dimensional array, the output result is not conducive to reading:

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$arr=array
(
    array("姓名"=>"张三","年龄"=>25,"性别"=>"男"),
    array("姓名"=>"李四","年龄"=>21,"性别"=>"男"),
    array("姓名"=>"娜娜","年龄"=>22,"性别"=>"女")
);
print_r($arr);
?>

Output Result:

Array ( [0] => Array ( [姓名] => 张三 [年龄] => 25 [性别] => 男 ) [1] => Array ( [姓名] => 李四 [年龄] => 21 [性别] => 男 ) [2] => Array ( [姓名] => 娜娜 [年龄] => 22 [性别] => 女 ) )

We can add a piece of code "echo '

';" before the print_r() output statement: <p><pre class="brush:php;toolbar:false"><?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$arr=array
(
    array("姓名"=>"张三","年龄"=>25,"性别"=>"男"),
    array("姓名"=>"李四","年龄"=>21,"性别"=>"男"),
    array("姓名"=>"娜娜","年龄"=>22,"性别"=>"女")
);
echo &#39;<pre class="brush:php;toolbar:false">&#39;;
print_r($arr);
?>

This way the output result will be more conducive to reading , Output result:

2. Use var_dump() to output the array

Same as print_r() function Similarly, the var_dump() function can also output the data content and structure of the entire array. However, var_dump() is more powerful than print_r(). It can print multiple variables at the same time and give the type information of the variables.

The var_dump() function can output relevant information (type and value) of variables. When outputting an array, the array will recursively expand the values ​​and display its structure through indentation.

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$arr=array
(
    array("姓名"=>"张三","年龄"=>25,"性别"=>"男"),
    array("姓名"=>"李四","年龄"=>21,"性别"=>"男"),
    array("姓名"=>"娜娜","年龄"=>22,"性别"=>"女")
);
var_dump($arr);
?>

Output result:

The difference between print_r() and var_dump():

Use print_r( ) function can print out the entire array content and structure, displaying keys and elements in a certain format. Note that the print_r() function is not just for printing, it is actually used to print easy-to-understand information about the variables.

var_dump() function can also be used to print the data and structure of the array. However, the var_dump() function is more powerful than print_r(). It can print multiple variables at the same time and give the type information of the variables.

var_dump() function displays structural information about one or more expressions, including the expression's type and value. Arrays will expand values ​​recursively, showing their structure through indentation.

Recommended learning: "

PHP Video Tutorial"

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