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How to get a single value from an array in php

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Release： 2023-03-22 11:54:02

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This article mainly shares with you the method of extracting a single value from an array in PHP. It is mainly shared with you in the form of code. I hope it can help you.

php takes out a single value from the array
1. Array arr
var_dump(arr) The value is as follows:

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 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>";
        }

    }
}

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

1. $object_json = json_encode($arr);得到的是对象   $json = json_encode($arr,true);得到的是纯json2. json_decode($object_json) 和 json_decode($json)得到的是数组对象
    json_decode($object_json,true) 和 json_decode($json,true)得到的是数组

综上 , 可以将数组对象转为数组的方式:

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arr,true), true);

项目中发现此问题 , 建议大家在php中将json和array转换时 , json_encode() 和 json_decode()的第二个参数要加 true , 即:

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json_encode(

##json,true);

“`

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