[英]Get total number of objects in JSON but Javascript Object.keys().length returns undefined
我正在尝试从REST服务从返回的JSON对象获取值。 当我尝试获取“行”或“记录”的数量(而不是键的数量Object.keys(json).length
时,使用Object.keys(json).length
时,我一直处于undefined
状态。
我已经在这些帖子中查看并尝试了以下一些答案:
这是我正在使用的代码:
$.getJSON(finalURL, function(json) {
console.log("json: " + json);
console.log("json.length: " + json.length);
var propertyNames = Object.keys(json).length;
console.log("propertyNames.length: " + propertyNames.length);
var jsonLength = propertyNames.length;
console.log("jsonLength: " + jsonLength);
if (isNaN(jsonLength)) {
console.log(jsonLength + " is not a number");
} else {
console.log(jsonLength + " is a number");
}
if (jsonLength > 0) {
console.log("jsonLength > 0");
} else {
console.log("jsonLength = 0");
}
});
这是返回的JSON:
{"id":1,"providerName":"Acme","providerID":"12343","providerLegacyID":"832940","contactName":"John Doe","contactEmail":"jdoe@this.eml","contactPhone":"3035551212","address1":"5999 Second Street","address2":"","city":"Denver","state":"CO","zip":"80203","providerKey":"0be32d8057924e718a8b6b4186254756","userKeys":null,"approved":null,"active":null,"createdBy":"Dan Zeller","createdByKey":"c6f4cf6a47a44092a3655420bd4a3f26","createdByRole":"ADMIN","createdDate":1517927130501,"updatedBy":null,"updatedByKey":null,"updatedByRole":null,"updatedDate":null,"removedBy":null,"removedByKey":null,"removedByRole":null,"removedByDate":null,"restoredBy":null,"restoredByKey":null,"restoredByRole":null,"restoredByDate":null}
因此,我期望上述JSON的JSON对象的长度为1。 如果返回更多,该数字将增加。
这是代码的输出:
json: [object Object]
json.length: undefined
propertyNames.length: undefined
jsonLength: undefined
undefined is not a number
jsonLength = 0
感谢任何帮助。
Object.keys(json)
返回一个数组,因此其.length
是一个数字。
您正在尝试获取数字的.length
,这没有任何意义。
你可以这样使用:
var myObject = {"id":1,"providerName":"Acme","providerID":"12343","providerLegacyID":"832940","contactName":"John Doe","contactEmail":"jdoe@this.eml","contactPhone":"3035551212","address1":"5999 Second Street","address2":"","city":"Denver","state":"CO","zip":"80203","providerKey":"0be32d8057924e718a8b6b4186254756","userKeys":null,"approved":null,"active":null,"createdBy":"Dan Zeller","createdByKey":"c6f4cf6a47a44092a3655420bd4a3f26","createdByRole":"ADMIN","createdDate":1517927130501,"updatedBy":null,"updatedByKey":null,"updatedByRole":null,"updatedDate":null,"removedBy":null,"removedByKey":null,"removedByRole":null,"removedByDate":null,"restoredBy":null,"restoredByKey":null,"restoredByRole":null,"restoredByDate":null};
var count = Object.keys(myObject).length;
console.log(count);
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