Question

我正在尝试将.push（）放到一个对象中的数组上。我怎么能这样做？

我有一个名为students {}的对象。其中的每一行都包含名字，姓氏，考试类型和该考试类型的主题。我正在尝试为此考试类型的学生创建所有科目的数组（studentSubjectsByName）。然后我想把那个主题数组放到另一个名为nameSearch {}的对象中。

数据库中的信息如下所示，

数据库表看起来像这样

> id    exam    subject             year    session     result  first   last
> 
> 186   A2  Further Mathematics 2015    January        D    Mark    Murphy
> 
> 185   A2  Pure Mathematics    2015    January        A    Mark    Murphy
> 
> 183   AP  Calculus            2015    NULL           2    Mark    Murphy
> 
> 184   AP  Chemistry           2015    NULL           5    David   Smith
> 
> 182   AP  Calculus            2015    NULL           5    David   Smith

（我无法发布图片，因为我没有10个代表。）

如你所见，马克在A2中有两个科目。

以下将主题推送到数组上，并导致三个主题是数组中的元素。每个科目都有一个阵列，但每个科目都有三个科目。而不是具有两个的AP阵列和仅具有一个应该是的A2阵列。这是因为var studentSubjectsByName = [];在for循环之外。

function checkStudent(){
    var subjectSearch = {};
    var nameSearch = {};
    var userInputFirst = document.getElementById('firstname').value;
    var userInputLast = document.getElementById('lastname').value;
    var students = <?php echo json_encode($studentNames, JSON_PRETTY_PRINT); ?>;
    var studentSubjectsByName = [];
    for(var i = 0; i < students.length; i++){

        console.log("userInputFirst: " + userInputFirst);
        if(userInputFirst == students[i].first && userInputLast == students[i].last){
            //console.log("First name: " + students[i].first + " Last name: " + students[i].last + " Exam: " + students[i].exam + " Subject: " + students[i].subject);

            nameSearch[students[i].exam] = {first:students[i].first, last:students[i].last, subjects:studentSubjectsByName};//this clears the array

            nameSearch[students[i].exam].subjects.push(students[i].subject);
            //console.log(studentSubjectsByName);
            //console.log(nameSearch);
       }
    }

    for(var item in nameSearch){
        var num = nameSearch[item].subjects.length;
        for(var i=0; i<num; i++){
            console.log("num: " + num + " nameSearch[" + item + "].subjects[" + i + "] is " + nameSearch[item].subjects[i]);
        }
    }
}

输出

userInputFirst：M

userInputFirst：Ma

userInputFirst：Mar

userInputFirst：标记

num：3 nameSearch [A2] .subjects [0]是Further Mathematics

num：3 nameSearch [A2] .subjects [1]是Pure Mathematics

num：3 nameSearch [A2] .subjects [2]是微积分

num：3 nameSearch [AP] .subjects [0]是Further Mathematics

num：3 nameSearch [AP] .subjects [1]是Pure Mathematics

num：3 nameSearch [AP] .subjects [2]是微积分

使用var studentSubjectsByName = [];在for循环中，数组不断被清除。

function checkStudent(){
    var subjectSearch = {};
    var nameSearch = {};
    var userInputFirst = document.getElementById('firstname').value;
    var userInputLast = document.getElementById('lastname').value;
    var students = <?php echo json_encode($studentNames, JSON_PRETTY_PRINT); ?>;

    for(var i = 0; i < students.length; i++){
         var studentSubjectsByName = [];
        console.log("userInputFirst: " + userInputFirst);
        if(userInputFirst == students[i].first && userInputLast == students[i].last){
            //console.log("First name: " + students[i].first + " Last name: " + students[i].last + " Exam: " + students[i].exam + " Subject: " + students[i].subject);

            nameSearch[students[i].exam] = {first:students[i].first, last:students[i].last, subjects:studentSubjectsByName};//this clears the array

            nameSearch[students[i].exam].subjects.push(students[i].subject);
            //console.log(studentSubjectsByName);
            //console.log(nameSearch);
       }
    }

    for(var item in nameSearch){
        var num = nameSearch[item].subjects.length;
        for(var i=0; i<num; i++){
            console.log("num: " + num + " nameSearch[" + item + "].subjects[" + i + "] is " + nameSearch[item].subjects[i]);
        }
    }
}

输出是。

userInputFirst：M

userInputFirst：Mar

userInputFirst：标记

num：1 nameSearch [A2] .subjects [0]是Pure Mathematics

num：1 nameSearch [AP] .subjects [0]是微积分

AP阵列中应该有两个主题，A2阵列中应该有一个主题。

HTML是，

<td class="left">
    First name: <input type="input" name="last" id="firstname" onkeyup="checkStudent()" placeholder="first name">
</td>
<td class="left">
    Last name: <input type="input" name="first" id="lastname" onkeyup="checkStudent()" placeholder="last name">
</td>

我无法弄清楚这一点。任何帮助，将不胜感激。感谢

Answer 1

你的问题不够明确。我正在直接回答你的头衔。

var ft = SupportFragmentManager.BeginTransaction();
ft.AddToBackStack(fragInfo.Tag);
ft.Commit();

Answer 2

查看更新的代码 - 我认为你有一个错字：

function checkStudent(){
    var nameSearch = {};
    var subjectSearch = {};
    var userInputFirst = document.getElementById('firstname').innerHTML;
    var userInputLast = document.getElementById('lastname').innerHTML;
    var students = [{ first: "first1", last: "last1", exam: "exam1", subject: "subject1"}, { first: "first2", last: "last2", exam: "exam2", subject: "subject2"}];
    for(var i = 0; i < students.length; i++){
        var studentSubjectsByName = [];
        if(userInputFirst == students[i].first && userInputLast == students[i].last){

            console.log("First name: " + students[i].first + " Last name: " + students[i].last + " Exam: " + students[i].exam + " Subject: " + students[i].subject);

            studentSubjectsByName.push(students[i].subject);  

            nameSearch[students[i].exam] = {first:students[i].first, last:students[i].last, subjects:studentSubjectsByName};

            nameSearch[students[i].exam].subjects.push(students[i].subject);
            console.log(studentSubjectsByName);
            console.log(nameSearch);
       }
    }
}

这是小提琴：https://jsfiddle.net/77er1a3r/

Answer 3

我无法使用.innerHTML

来解决这个问题

var userInputFirst = document.getElementById('firstname').innerHTML;
var userInputLast = document.getElementById('lastname').innerHTML;
console.log("first: " + userInputFirst + " last: " + userInputLast);

但它确实有用，基本上是.value

var userInputFirst = document.getElementById('firstname').value;
var userInputLast = document.getElementById('lastname').value;
console.log("first: " + userInputFirst + " last: " + userInputLast);

HTML是，

名字：姓：

我是否使用.value代替.innerHTML前面提到的类型？感谢

.push到对象

3 个答案: