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How to get a single value from an array in php

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Release： 2023-03-21 10:54:01

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How to extract a single value from an array in php. Below, I will share with you a method for extracting a single value from an array in php. It has a good reference value and I hope it can help you.

1. Array arr

var_dump(arr) has the following values:

array (size=3)
 &#39;delete&#39; => 
 array (size=3)
  0 => string &#39;HBSFlyRecode20170222-101501.txt&#39; (length=31)
  1 => string &#39;HBSFlyRecode20170222-105502.txt&#39; (length=31)
  2 => string &#39;HBSFlyRecode20170222-108803.txt&#39; (length=31)
 &#39;new&#39; => 
 array (size=3)
  0 => string &#39;HBSFlyRecode20170223-101504.txt&#39; (length=31)
  1 => string &#39;HBSFlyRecode20170223-105505.txt&#39; (length=31)
  2 => string &#39;HBSFlyRecode20170223-108806.txt&#39; (length=31)
 &#39;old&#39; => 
 array (size=3)
  0 => string &#39;HBSFlyRecode20170221-101507.txt&#39; (length=31)
  1 => string &#39;HBSFlyRecode20170221-105508.txt&#39; (length=31)
  2 => string &#39;HBSFlyRecode20170221-108809.txt&#39; (length=31)

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echo $arr[&#39;old&#39;][0];
打印出: HBSFlyRecode20170221-101507.txt

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But if arr is in object form, the print result is as follows:

var_dump(arr)
object(stdClass)[1]
 public &#39;delete&#39; => 
 array (size=3)
  0 => string &#39;HBSFlyRecode20170222-101501.txt&#39; (length=31)
  1 => string &#39;HBSFlyRecode20170222-105502.txt&#39; (length=31)
  2 => string &#39;HBSFlyRecode20170222-108803.txt&#39; (length=31)
 public &#39;new&#39; => 
 array (size=3)
  0 => string &#39;HBSFlyRecode20170223-101504.txt&#39; (length=31)
  1 => string &#39;HBSFlyRecode20170223-105505.txt&#39; (length=31)
  2 => string &#39;HBSFlyRecode20170223-108806.txt&#39; (length=31)
 public &#39;old&#39; => 
 array (size=3)
  0 => string &#39;HBSFlyRecode20170221-101507.txt&#39; (length=31)
  1 => string &#39;HBSFlyRecode20170221-105508.txt&#39; (length=31)
  2 => string &#39;HBSFlyRecode20170221-108809.txt&#39; (length=31)

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You cannot use $arr['old'][0] to get the value, you can use the arr object The value of the foreach method that is common to arrays:

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

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

1. $object_json = json_encode($arr); what you get is the object

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

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

json_decode($object_json,true) and json_decode($json,true) It’s an array

To sum up, you can convert an array object into an array:

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

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project I found this problem in . It is recommended that when converting json and array in php, you should add true to the second parameter of json_encode() and json_decode(), that is:

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

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