PHP100 2019-03-28
1.数组arr
var_dump(arr) 值如下:
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
但是如果arr是对象形式 , 打印结果如下:
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)
就不能使用 $arr[‘old'][0] 取值了 , 可以使用arr对象和数组通用的foreach方式取值:
function getValue($arr){ foreach($arr as $key => $value){ if(is_array($value)){ getValue($value); }else{ echo $value."<br>"; } } }
如果arr为对象形式 , 可以考录将对象转为数组形式 , 这里提供一种快捷方式:
1. $object_json = json_encode($arr);得到的是对象
$json = json_encode($arr,true);得到的是纯json
2. 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:
arr=jsondecode(jsonencode(arr=jsondecode(jsonencode(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:
json_encode(arr,true);jsondecode(arr,true);jsondecode(json,true);