How to output a mixed array in php

In the PHP development process, we often need to deal with mixed arrays, which contain both numeric index arrays and associative arrays. How to output such a mixed array? This article will introduce you to several commonly used methods.

Method 1: Use print_r to output

Print_r is a built-in function in PHP that can print out an array in an easy-to-read form. We can output mixed arrays through print_r. The following is a sample code:

$arr = array(
    'id' => 1,
    'name' => '张三',
    'age' => 18,
    'hobbies' => array('足球', '篮球', '乒乓球'),
    0 => '数字索引1',
    1 => '数字索引2'
);
print_r($arr);

The output result is:

Array
(
    [id] => 1
    [name] => 张三
    [age] => 18
    [hobbies] => Array
        (
            [0] => 足球
            [1] => 篮球
            [2] => 乒乓球
        )

    [0] => 数字索引1
    [1] => 数字索引2
)

We can see that print_r prints the mixed array in the form of a hierarchical structure, which can clearly and intuitively display each element in the array. element.

Method 2: Use var_dump to output

Similar to print_r, var_dump is also a PHP built-in function that can print out arrays. The difference is that var_dump can output detailed information such as the type and length of each element. The following is a sample code:

$arr = array(
    'id' => 1,
    'name' => '张三',
    'age' => 18,
    'hobbies' => array('足球', '篮球', '乒乓球'),
    0 => '数字索引1',
    1 => '数字索引2'
);
var_dump($arr);

The output result is:

array(6) {
  ["id"]=>
  int(1)
  ["name"]=>
  string(6) "张三"
  ["age"]=>
  int(18)
  ["hobbies"]=>
  array(3) {
    [0]=>
    string(6) "足球"
    [1]=>
    string(6) "篮球"
    [2]=>
    string(9) "乒乓球"
  }
  [0]=>
  string(5) "数字索引1"
  [1]=>
  string(5) "数字索引2"
}

As you can see from the output result, the information output by var_dump is more detailed, including the type, length and other information of the element, but the output result The format is not clear enough.

Method 3: Use json_encode to output

We can also use the json_encode function to convert the array into a string in JSON format and output it. The following is a sample code:

$arr = array(
    'id' => 1,
    'name' => '张三',
    'age' => 18,
    'hobbies' => array('足球', '篮球', '乒乓球'),
    0 => '数字索引1',
    1 => '数字索引2'
);
echo json_encode($arr);

The output result is:

{"id":1,"name":"u5f20u4e09","age":18,"hobbies":["u8db3u7403","u7beeu7403","u4e58u4e50u7403"],"0":"u6570u5b57u7d22u5f151","1":"u6570u5b57u7d22u5f152"}

As you can see from the output result, the json_encode function converts the array into a string in JSON format and outputs it using Unicode encoding. It should be noted that json_encode only supports UTF-8 encoded strings.

Summary

The above are several common methods of outputting mixed arrays. We can choose the appropriate method according to actual needs. During the development process, outputting arrays reasonably can help us quickly locate problems and improve development efficiency.

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