JSON traversal method example summary_javascript skills

The example in this article summarizes the JSON traversal method. Share it with everyone for your reference, the details are as follows:

The first method: use for loop

js code:

function CyclingJson1() { 
 var testJson = '[{ "name": "小强", "age": 16 },{"name":"小明","age":17}]'; 
 testJson = eval("(" + testJson + ")"); 
 for (var i = 0; i < testJson.length; i++) { 
  alert(testJson[i].name); 
 } 
} 

Second type: Use the keyword in

js code:

function CyclingJson2() {
 var testJson = '[{ "name": "小强", "age": 16 },{"name":"小明","age":17}]'; 
 testJson = eval("(" + testJson + ")");
 for (var i in testJson) {
  alert(testJson[i].name);
 }
}

Third method; use jquery.each() function

function CyclingJson3() {
 var testJson = '[{ "name": "小强", "age": 16 },{"name":"小明","age":17}]';
 testJson = eval("(" + testJson + ")");
 $.each(testJson, function (i, n) {
  alert(i); //i为索引值
  alert(n.name); //n为遍历的值
 });
}

Comprehensive example:

<script language="javascript" type="text/javascript">
var array = { "a": "abc", "b": [1, 2, 3, 4, 5, 6], "c": 3, "d": { "name": "james", "age": 28},"e":null,"f":true };
var arrayObj = { "a": { "name": "kobe", "age": 34 }, "b": { "name": "lofo", "age": 28} };
//遍历array方式1
for (var x in array) {
 if (typeof array[x] == 'object' && array[x] != null ) {
  for (var y in array[x]) {
   alert("key = " + y + " value = " + array[x][y]);
  }
 } else {
  alert("key = " + x + " value = " + array[x]); // 非array object
 }
}
//遍历array方式2
$.each(array, function(k, v) {
 var a = typeof (v);
 //数组与对象为object类型，其他分别是string与number类型
 //此时的k代表a、b、c、d，v代表对应的值
 if (typeof (v) == "object") {
  //获取数组与对象后，再去遍历这个数组与对象
  $.each(v, function(k1, v1) {
   window.alert("key = " + k1 + " value=" + v1);
  });
 } else {
  window.alert("key = " + k + " value=" + v);
 }
});
//遍历arrayObj方式1
for (var x in arrayObj) {
 for (var key in arrayObj[x]) {
  window.alert("key=" + key + " value=" + arrayObj[x][key]);
 }
}
//遍历arrayObj方式2
$.each(arrayObj, function(key, value) {
 $.each(value, function(k, v) {
  window.alert("key=" + k + " value=" + v);
 });
});
//遍历arrayObj方式3
$.each(arrayObj, function(key, value) {
 window.alert("key=" + key + " valueName=" + value.name + " valueAge=" + value.age);
});
</script>
<script language="javascript" type="text/javascript">
var UserList = [
 { "UserID": 11, "Name": { "FirstName": "Truly", "LastName": "Zhu" }, "Email": "" },
 { "UserID": 12, "Name": { "FirstName": "Jeffrey", "LastName": "Richter" }, "Email": "" },
 { "UserID": 13, "Name": { "FirstName": "Scott", "LastName": "Gu" }, "Email": "" }
]
$.each(UserList, function(k, v) {
 $.each(v, function(k1, v1) {
  if (typeof (v1) == "object") {
   $.each(v1, function(k2, v2) {
    window.alert("key=" + k2 + " value=" + v2);
   });
  } else {
   window.alert("key=" + k1 + " value=" + v1);
  }
 });
});
</script>
<script language="javascript" type="text/javascript">
var userArray = [
 { "UserID": 11, "Name": { "FirstName": "Truly", "LastName": "Zhu" }, "Email": "" },
 { "UserID": 12, "Name": { "FirstName": "Jeffrey", "LastName": "Richter" }, "Email": "" },
 { "UserID": 13, "Name": { "FirstName": "Scott", "LastName": "Gu" }, "Email": "" }
];
for (var i in userArray) {
 for (var k in userArray[i]) {
  if (typeof userArray[i][k] == "object" && userArray[i][k] != null) {
   for (var j in userArray[i][k]) {
    window.alert("key=" + j + "--value=" + userArray[i][k][j]);
   }
  } else {
   window.alert("key=" + k + "--value=" + userArray[i][k]);
  }
 }
}
</script>

I hope this article will be helpful to everyone in JavaScript programming.