Javascript 如何循环遍历 JSON 数组？
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How to loop through JSON array?
提问by pal
I have some JSON-code which has multiple objects in it:
我有一些 JSON 代码，其中包含多个对象：
[
{
"MNGR_NAME": "Mark",
"MGR_ID": "M44",
"EMP_ID": "1849"
},
{
"MNGR_NAME": "Steve",
"PROJ_ID": "88421",
"PROJ_NAME": "ABC",
"PROJ_ALLOC_NO": "49"
}
]
My JSON loop snippet is:
我的 JSON 循环片段是：
function ServiceSucceeded(result)
{
for(var x=0; x<result.length; x++)
{
}
}
Could you please let me know how to check there is no occurence of "MNGR_NAME" in the array. (It appears twice in my case.)
您能否让我知道如何检查数组中没有出现“MNGR_NAME”。（在我的情况下它出现了两次。）
回答by Abdul Munim
You need to access the resultobject on iteration.
您需要result在迭代时访问该对象。
for (var key in result)
{
if (result.hasOwnProperty(key))
{
// here you have access to
var MNGR_NAME = result[key].MNGR_NAME;
var MGR_ID = result[key].MGR_ID;
}
}
回答by Kees C. Bakker
You could use jQuery's $.each:
你可以使用 jQuery 的$.each：
var exists = false;
$.each(arr, function(index, obj){
if(typeof(obj.MNGR_NAME) !== 'undefined'){
exists = true;
return false;
}
});
alert('Does a manager exists? ' + exists);
Returning falsewill break the each, so when one manager is encountered, the iteration will stop.
返回false将破坏 each，因此当遇到一个 manager 时，迭代将停止。
回答by Thomas Johan Eggum
Note that your object is an array of JavaScript objects. Could you use something like this?
请注意，您的对象是一个 JavaScript 对象数组。你能用这样的东西吗？
var array = [{
"MNGR_NAME": "Mark",
"MGR_ID": "M44",
"EMP_ID": "1849"
},
{
"MNGR_NAME": "Steve",
"PROJ_ID": "88421",
"PROJ_NAME": "ABC",
"PROJ_ALLOC_NO": "49"
}];
var numberOfMngrName = 0;
for(var i=0;i<array.length;i++){
if(array[i].MNGR_NAME != null){
numberOfMngrName++;
}
}
console.log(numberOfMngrName);
回答by user1349544
Use ES6...
使用 ES6...
myobj1.map(items =>
{
if(items.MNGR_NAME) {
return items.MNGR_NAME;
}else {
//do want you want.
}
})
Thanks.
谢谢。
回答by jabclab
This will find the number of occurrences of the MNGR_NAMEkey in your ObjectArray:
这将MNGR_NAME在您的 中找到键的出现次数ObjectArray：
var numMngrName = 0;
$.each(json, function () {
// 'this' is the Object you are iterating over
if (this.MNGR_NAME !== undefined) {
numMngrName++;
}
});
回答by Alex K.
Within the loop result[x]is the object, so if you wanted to count a member that may or may not be present;
循环内result[x]是对象，所以如果你想计算一个可能存在也可能不存在的成员；
function ServiceSucceeded(result)
{
var managers = 0
for(var x=0; x<result.length; x++)
{
if (typeof result[x].MNGR_NAME !== "undefined")
managers++;
}
alert(managers);
}
回答by kgiannakakis
You could use $.each or $.grep, if you also want to get the elements that contain the attribute.
如果您还想获取包含该属性的元素，则可以使用 $.each 或 $.grep。
filtered = $.grep(result, function(value) {
return (value["MNGR_NAME"] !== undefined)
});
count = filtered.length
回答by Steffen Stenersen
You can iterate over the collection and check each object if it contains the property:
您可以遍历集合并检查每个对象是否包含该属性：
var count = 0;
var i;
for(i = 0; i < jsonObj.length; i += 1) {
if(jsonObj[i]["MNGR_NAME"]) {
count++;
}
}
Working example: http://jsfiddle.net/j3fbQ/
工作示例：http: //jsfiddle.net/j3fbQ/
