PHP method to extract a single value from an array

This time I will bring you the analysis of the method of retrieving a single value from an array in PHP. What are the precautions for retrieving a single value from an array in PHP? The following is a practical case, let's take a look.

1. The value of array arr

var_dump(arr) is as follows:

array (size=3)
 'delete' => 
 array (size=3)
  0 => string 'HBSFlyRecode20170222-101501.txt' (length=31)
  1 => string 'HBSFlyRecode20170222-105502.txt' (length=31)
  2 => string 'HBSFlyRecode20170222-108803.txt' (length=31)
 'new' => 
 array (size=3)
  0 => string 'HBSFlyRecode20170223-101504.txt' (length=31)
  1 => string 'HBSFlyRecode20170223-105505.txt' (length=31)
  2 => string 'HBSFlyRecode20170223-108806.txt' (length=31)
 'old' => 
 array (size=3)
  0 => string 'HBSFlyRecode20170221-101507.txt' (length=31)
  1 => string 'HBSFlyRecode20170221-105508.txt' (length=31)
  2 => string 'HBSFlyRecode20170221-108809.txt' (length=31)

echo $arr['old'][0];
打印出: HBSFlyRecode20170221-101507.txt

But if arr is in the form of

object, print The result is as follows:

var_dump(arr)
object(stdClass)[1]
 public 'delete' => 
 array (size=3)
  0 => string 'HBSFlyRecode20170222-101501.txt' (length=31)
  1 => string 'HBSFlyRecode20170222-105502.txt' (length=31)
  2 => string 'HBSFlyRecode20170222-108803.txt' (length=31)
 public 'new' => 
 array (size=3)
  0 => string 'HBSFlyRecode20170223-101504.txt' (length=31)
  1 => string 'HBSFlyRecode20170223-105505.txt' (length=31)
  2 => string 'HBSFlyRecode20170223-108806.txt' (length=31)
 public 'old' => 
 array (size=3)
  0 => string 'HBSFlyRecode20170221-101507.txt' (length=31)
  1 => string 'HBSFlyRecode20170221-105508.txt' (length=31)
  2 => string 'HBSFlyRecode20170221-108809.txt' (length=31)

You cannot use $arr['old'][0] to get the value. You can use the

foreach method common to arr objects and arrays to get the value:

function getValue($arr){
 foreach($arr as $key => $value){
  if(is_array($value)){
   getValue($value);
  }else{
   echo $value."<br>";
  }
 }
}

If arr is in object form, you can convert the object into array form. Here is a shortcut:

1. $object_json = json_encode ($arr); What you get is an object

$json = json_encode($arr,true); What you get is pure json

2. json_decode($object_json) and json_decode($json) What is obtained is an array object

json_decode($object_json,true) and json_decode($json,true) is obtained is an array

To sum up, the array object can be converted For arrays: This problem was found in the

arr=jsondecode(jsonencode(arr=jsondecode(jsonencode(arr,true),true);

project. It is recommended that when converting json and array in php, the second parameter of json_encode() and json_decode() should be added. true , that is:

json_encode(arr,true);jsondecode(arr,true);jsondecode(json,true);

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website!

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The above is the detailed content of PHP method to extract a single value from an array. For more information, please follow other related articles on the PHP Chinese website!