對象數組中的Javascript對象與console.log不同

Question

我的代碼：

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Test</title>
</head>

<body>
    <script>
        var students = [];
        var student = {};
        var scores = [];
        var final = [];

        function setStudent(name , score) {
            student = {"Name": name, "Score": score};
            //student.Name = name;
            //student.Score = score;
            document.write(student.Name + " scored " + student.Score + ".<br>");
            final.push(student);
            return student;

        }


        for (var i=0; i<4; i++) {
            students.push(prompt("Please Enter student name"));
        }

        for (var i=0; i<4; i++) {
            scores.push(prompt("Please Enter "+ students[i] +"'s score" ))
        }
        for (var i=0; i<4; i++) {
            setStudent(students[i],scores[i]);

        }

        console.log(final);
    </script>
</body>
</html>

這是第一個有效的版本，控制台輸出如下：可以在http://i.imgur.com/HnEHX5J.png中找到圖像

而第二個版本是：

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Test</title>
</head>

<body>
    <script>
        var students = [];
        var student = {};
        var scores = [];
        var final = [];

        function setStudent(name , score) {
            //student = {"Name": name, "Score": score};
            student.Name = name;
            student.Score = score;
            document.write(student.Name + " scored " + student.Score + ".<br>");
            final.push(student);
            return student;

        }


        for (var i=0; i<4; i++) {
            students.push(prompt("Please Enter student name"));
        }

        for (var i=0; i<4; i++) {
            scores.push(prompt("Please Enter "+ students[i] +"'s score" ))
        }
        for (var i=0; i<4; i++) {
            setStudent(students[i],scores[i]);

        }

        console.log(final);
    </script>
</body>
</html>

該版本的輸出是：您可以在https://i.stack.imgur.com/0mQFz.png中找到圖像

萬一您不知道更改了什么，請看一下分配對象的函數。我的問題是為什么輸出不同。

Answer 1

你不聲明變量student的內部setStudent功能。 因此，變量student是在全局對象window上定義的。 當您運行此方法時，您每次都使用相同的指針，從而更改相同指針的值並將相同對象重新添加到數組中。

要解決此錯誤，只需將一個student聲明為空對象字面量{}

我的問題是為什么輸出不同

輸出之所以不同，是因為document.write會將當前時間點的對象轉換為string 。 在console.log ，當您擴展console.log的箭頭時，將捕獲對象的子屬性。 如果克隆的對象或使用JSON.stringify每次轉讓后，然后console.log GED它們，然后輸出console.log將如預期。

 var students = []; var student = {}; var scores = []; var final = []; function setStudent(name, score) { //student = {"Name": name, "Score": score}; // ERROR HERE // you're not declaring the variable `student` therefore, the variable `student` is defined on the global object `window`. When you run this method, you're using the same pointer every time and thus changing the pointer and readding it to the array. var student = {}; // this is the fix student.Name = name; student.Score = score; document.write(student.Name + " scored " + student.Score + ".<br>"); final.push(student); return student; } for (var i = 0; i < 4; i++) { students.push(prompt("Please Enter student name")); } for (var i = 0; i < 4; i++) { scores.push(prompt("Please Enter " + students[i] + "'s score")) } for (var i = 0; i < 4; i++) { setStudent(students[i], scores[i]); } console.log(final);

對象數組中的Javascript對象與console.log不同

問題描述

1 個解決方案

解決方案1
0 已采納 2017-05-30 03:27:07

對象數組中的Javascript對象與console.log不同

問題描述

1 個解決方案

解決方案1 0 已采納 2017-05-30 03:27:07

解決方案1
0 已采納 2017-05-30 03:27:07