我有一个数组，可以解答给定问题的学生答案。
如果学生给出答案，它会被插入到当前索引的数组中，如[
"answer",
undefined, // student has not given answer
"answer2",
]
之后，我可以读取数组并将条目映射到给定的问题数组
这种情况：
if (answers[questionindex] === undefined)的工作原理。 （循环遍历数组，只输出“没有给出答案”undefined
但是当LAST答案未定义（1个或更多）时它不起作用 他们只是不存在（当然）。
如何将这些字段设置为var testResults = {
addRoom: function(Id, teacher) { // room pseudoconstructor
this[Id] = {
created: moment(),
runningProblem: false,
time: 0, // holds the countdown for the current problem
getTime: function() { // returns the countdown-counter
return this.time;
},
Id: Id,
teacher: teacher,
getCurrentSolution: function() {
return math.eval(this.testProblems[this.getCurrentProblemIndex()].problem);
},
getTimeTaken: function() {
return this.getCurrentProblemTimeLimit() - this.time;
},
getCurrentProblemTimeLimit: function() {
return this.testProblems[this.getCurrentProblemIndex()].timeLimit;
},
getCurrentProblemIndex: function() {
return this.testProblems.length - 1;
},
addTestProblem: function(problem, timeLimit) {
var solution = math.eval(problem);
this.testProblems.push({problem: problem, timeLimit: timeLimit, solution: solution});
console.dir(this.testProblems);
},
testProblems: [],
updatePercentages: function(name) {
function round(num) {
return +(Math.round(num + "e+2") + "e-2");
}
console.log('updating percentages');
console.log('answers length ' + this.students[name].givenAnswers.length);
var timeSum = 0;
for(var i = 0; i < this.students[name].givenAnswers.length; i++ ) {
timeSum += this.students[name].givenAnswers[i].takenTime;
}
var timeAvg = timeSum / this.students[name].givenAnswers.length;
console.log('timeAvg for ' + name + ' ' + timeAvg);
this.students[name].avgTime = round(timeAvg);
var correctSum = 0;
for(var j = 0; j < this.students[name].givenAnswers.length; j++ ) {
if (this.students[name].givenAnswers[j].correct) {
correctSum++;
}
}
var correctAvg = correctSum / this.students[name].givenAnswers.length;
console.log('correctAvg for ' + name + ' ' + correctAvg);
this.students[name].avgCorrect = round(correctAvg) * 100;
},
addGivenStudentAnswer: function(name, answer, takenTime, index) {
console.log('adding answer ' + name + ' ' +answer+ ' ' + takenTime);
var correct = this.getCurrentSolution() == answer;
if (typeof this.students[name].givenAnswers[index] === 'undefined') {
this.students[name].givenAnswers[index] = ({
answer: answer,
takenTime: takenTime,
correct: correct
});
this.updatePercentages(name);
//console.dir(this.students[name].givenAnswers);
return true;
} else {
console.log('attempt at double answer. not saved');
return false;
}
},
addStudent: function(name) {
if (!(this.students[name])) {
this.students[name] = {
studentName : name,
avgTime: 0,
avgCorrect: 0,
givenAnswers: []
}
}
console.dir(this);
},
students: {}
};
console.dir(this);
},
deleteRoom: function(Id) {
delete this[Id];
console.log('room deleted from testResults');
}
};
（例如，在计时器达到零之后），以显示没有给出答案？
现在，平均值计算显示3个给定（正确）的100％正确，然后2个未给出
码
// after test var name = socket.userName;
var room = socket.room;
var created = testResults[room].created;
var students = testResults[room].students;
var problems = testResults[room].testProblems;
var test = new tests({
roomId : room,
created : created,
teacher : name,
students : students,
problems : problems
});
test.save(function(err, result) {
if (err) {console.log(err);}
else {
console.log('test saved to DB');
socket.emit('testSaved');
// delete from roomList
testRooms.deleteRoom(room, name);
// delete from resultObject
testResults.deleteRoom(room);
// answer
io.in(room).emit('room Closed');
}
});
router.get('/showtests/:roomId', function(req, res) {
if (req.user && req.user.role === 'teacher') {
tests.findOne({roomId: req.params.roomId}, {}, function(err, result) {
if (err) {console.log(err);}
res.render('showSingleTest', {user: req.user, testData: JSON.parse(JSON.stringify(result))});
})
} else {
res.render('customerror', { title: "Error", errMsg1: "error.error", errMsg2: "error.notLoggedIn" });
}
});
从DB afterwars读取测试的路线
h2(data-i18n="markup.studentsAnswers")
each student in testData.students
.testViewSingleStudentAnswers.col-md-6
h3 #{student.studentName}
ol.answers
each answer in student.givenAnswers
if (answer)
if (answer.correct == true)
li.correct
span #{answer.answer}
|
span.floatRight (#{answer.takenTime}s)
else
li.wrong
span #{answer.answer}
|
span.floatRight (#{answer.takenTime}s)
else
li.noAnswer(data-i18n="markup.noAnswerGiven")
.testTotals
| #{student.avgCorrect}
span(data-i18n="markup.percentCorrect")
| ,
| #{student.avgTime}
span(data-i18n="markup.avgTime")
aaaaa和玉
{{1}}
答案 0 :(得分：2)
你可以这样做：
function push_answer(answer){
answer = answer || "undefined"
array_of_answers.push(answer)
}
现在，该值未定义，但由文字定义。你可以用一些unicode字符替换它，以防某些答案可以是＆＃34; undefined＆＃34;。
度过美好的一天！
答案 1 :(得分：0)
似乎对我没有问题。
HTML：
<div id="content">
</div>
JS：
var answers = ["answer1","answer2",undefined,"answer3",undefined];
for(i=0;i<answers.length;i++) {
if(!answers[i]){
answers[i]="no answer";
}
}
document.getElementById('content').innerHTML = answers;
答案 2 :(得分：0)
我的个人推荐：＆＃34;永远不要把事情弄清楚＆＃34;
如果学生没有选择答案，你应该用“＆＃39;”填充该空白区域，因为未定义真的很难处理，所以为了填补空白：
这将检查答案是否为＆＃34;未定义＆＃34;用＆＃39;填补空白（空白），然后，当你检查答案时，评估会更简单......
Sub taskupdateMacro(item As Outlook.MailItem)
Dim olkApp, olkNS, olkTaskFolder, objItem, olkTaskUpdate, olkTask
Dim objCount
objCount = 0
Set olkApp = CreateObject("Outlook.Application")
Set olkNS = olkApp.GetNamespace("MAPI")
olkNS.Logon "Outlook"
Set olkTaskFolder = olkNS.GetDefaultFolder(6)
For Each objItem In olkTaskFolder.Items
If (objItem.Class = 50 Or objItem.Class = 51 Or objItem.Class = 43) Then
objCount = objCount + 1
objItem.Display
objItem.Close 1
End If
Next
If objCount = 0 Then
MsgBox "No Task Related Emails to Open"
End If
Set objItem = Nothing
Set olkTaskFolder = Nothing
Set olkTaskRequest = Nothing
Set olkTask = Nothing
olkNS.Logoff
Set olkNS = Nothing
Set olkApp = Nothing
End Sub