First of all, I am very new to programming so apologies in advance.
This is what I am trying to do:
1) Generate a random value into a variable using
questionNr = Random.Range(0, nNodes);
2) Compare that variable to an array by iterating through all its values
for(var i=0; i<usedQuestionList.length(); i++){
if(questionNr == usedQuestionList[i]){
//stuff
}
}
3) If any value of the array is equal to said variable's value, start from the beginning by generating a new random value and loop through the array again. The only way to pass/end the loop is when the random value is NOT equal to any of the values in the array.
The problem is that if I do this simple for loop, there's no way for me to go back and do everything again when the conditions are not met.
I'm pretty sure I'm just approaching the logic wrong and there's a simple way to do this that hasn't occurred to me, that's why I'm not adding any of the code from my failed for and while loop attempts. Any help appreciated, thanks!
You can set a flag that you can check after the loop has finished, maybe something like this:
//A function that will take a number and check against the array
var loopRandomNumber = function(number){
//A flag to be used if match is found
var foundMatch = false;
//Your simple loop
for(var i=0; i<usedQuestionList.length(); i++){
//Checking if match
if(number == usedQuestionList[i]){
foundMatch = true; //Match found
break; // Jumps out of the for-loop to be a little faster
}
}
//Calling this function again with a new random number if match found
if(foundMatch){
loopRandomNumber(Random.Range(0, nNodes));
} else {
//Handle your condition for if no match was found here
}
}
loopRandomNumber(Random.Range(0, nNodes));
Related
Basically i have to create a quiz with 3category. each with 5questions.
I would have to push the selected category-questions into this new array from the array with all the questions. I am unable to do so.
pushSelectedQuestion() {
for (var i = 0; i < this.getNumberOfQuestion; i++) {
if (usercategory == questionPool[i].category) {
mcqSelected.push(questionPool[i])
return mcqSelected;
}
}
}
usercategory = input from user.
if user chooses category 1.
if (1 == questionPool[1].category) (if it matches the category) then it will be pushed.
This is the part which i cant do
Well, from the information you've provided, there's one main issue here - the return statement is definitely shortcutting the loop - so even if you have everything else right, you'll only ever get the first matching question. The rest will have been cut out by the return statement, which stops the function and returns the value.
pushSelectedQuestion() {
for (var i = 0; i < this.getNumberOfQuestion; i++) {
if (usercategory == questionPool[i].category) {
mcqSelected.push(questionPool[i])
// the below line is causing this loop to end after the first time through the list.
// Remove it and then put a console.log(mcqSelected);
// here instead to see the value during each iteration of the loop.
return mcqSelected;
}
}
}
There are a lot of ways to accomplish what you want to do here though. For example, you could just use the javascript Array.filter method like so
let selectedQuestions = questionPool.filter(question => question.category == userCategory)
Maybe I am not understanding your question correctly, but can't you use nested arrays. If the questions are categorized beforehand that is.
So I have a simple program to change the value of an input field every time you blur it. It logs the already used values in an array, an I use that array to check if it's been used. It practically works as intended, but after a few tries it will return true and logs, yet the value wont change.
Updated Code:
var dftvalue = ['Freddy the Grocer', 'Jack the Fiddler', 'Cane the Sheep Herder', 'Arnold the Fish Monger', 'Luke the Car Salesman', 'Josh the Tailor', 'Carol the Baker', 'Tiara the Nacho Vendor', 'example#email.com', 'Your message here.'];
var logused = new Array(); //create new array to log the used indexs
function setdftvalue() {
var newval = dftvalue[Math.floor(Math.random() * 7)];
if (logused.indexOf(newval) == -1) {
this.value=newval;
logused.push(newval);
console.log(logused);
} else if (logused.indexOf(newval) >= 0) {
setdftvalue();
}
if (logused.length == 8) {
for (i=0; i<=7; i++){
logused.pop();
}
}
}
document.getElementById('formname').onblur=setdftvalue;
JSFIDDLE
https://jsfiddle.net/e5pdz37e/8/
Your approach is unnecessarily complicated. At a high level I would recommend an approach that's more like this:
function setdftvalue() {
if (index === (dftvalue.length - 1)) {
// Shuffle your names array
index = -1;
}
input.value = dftvalue[++index];
}
This way you won't need to use any recursion and make unnecessary function calls. And the only time you'll need to randomize is when you've used up all of your available names.
Here's a working example: http://jsfiddle.net/bvaughn/163mqdeL/
Original answer
After a few invocations, your function will fill up the logused Array, at which point calling it again will do nothing. Actually, worse than nothing - it will recursively call itself without end.
So I am doing an assignment for a required javascript class and am stuck on a couple of parts specifically. We are supposed to create a guessing game with an array where we prompt the user to guess names and if they match anything in the array to tally it up as points.
Anyway here is the main code, the part that I am stuck on is figuring out how to loop the code so when the user is prompted 3 times for a guess and each guess is taken into account
var sportsArray = ["Football","Basketball","Rollerblading","Hiking","Biking","Swimming"];
var name = prompt("Please enter your name.", "Enter Here");
var arrayGuess = prompt("Guess a sport.", "Enter Here");
var counter;
for (counter = 0; counter < sportsArray.length; counter++) {
if (arrayGuess === "Football"||"Basketball"||"Rollerblading"||"Hiking"||"Biking"||"Swimming"){
alert("Good Job");
} else {
arrayGuess;
}
}
So the goal is to prompt the user to guess a part of the original array and if they do let them know that, but if they don't take points away and make them guess again until they have guessed 3 times.
Anyway if someone could lend a hand it would be appreciated.
You cannot simultaneously compare one item to a whole bunch of things like this:
if (arrayGuess === "Football"||"Basketball"||"Rollerblading"||"Hiking"||"Biking"||"Swimming")
Instead, you have to compare it to each individual item:
if (arrayGuess === "Football"||
arrayGuess === "Basketball"||
arrayGuess === "Rollerblading"||
arrayGuess === "Hiking"||
arrayGuess === "Biking"||
arrayGuess === "Swimming")
Or, there are more effective ways to compare to multiple items such as:
if (" Football Basketball Rollerblading Hiking Biking Swimming ".indexOf(" " + arrayGuess + " ") !== -1)
Or, using an array:
if (["Football","Basketball","Rollerblading","Hiking","Biking","Swimming"].indexOf(arrayGuess) !== -1)
Or, if this comparison happened a lot, you'd build an object ahead of time and use it for a lookup:
var items = {"Football":true,"Basketball":true,"Rollerblading":true,"Hiking":true,"Biking":true,"Swimming":true};
if (items[arrayGuess] === true)
If you want to compare without regards for proper case, then you can lowercase what the user entered and compare that to lower case test values:
var items = {"football":true,"basketball":true,"rollerblading":true,"hiking":true,"biking":true,"swimming":true};
if (items[arrayGuess.toLowerCase()] === true)
FYI, it's also not clear why you're using a loop here at all. No loop is needed to prompt once and test against all the possible sports values.
If you have to cycle through an array with a loop, then you can do this:
var items = ["football","basketball","rollerblading","hiking","biking","swimming"];
var testVal = arrayGuess.toLowerCase();
var match = -1;
for (var i = 0; i < items.length; i++) {
if (testVal === items[i]) {
// found a match
match = i;
break;
}
}
if (match !== -1) {
// items[match] was the match
} else {
// no match
}
I see a couple of things wrong here, as was already mentioned, your comparison in the if statement needs to reference the variable each time it is compared. But additionally, since you are in a loop based on the length of your sportsArray variable, it would be better to not reference strings at all in the if statement, and instead do something more like the following:
if (arrayGuess === sportsArray[counter]) {
// Do stuff here
} else {
// Do other stuff here
}
Additionally, your else clause isn't going to behave quite like you are expecting it to. You are going to have to assign a new value to it, probably by way of another call to prompt. As of now you are only referencing the variable, which will do nothing. If you need to take three guesses, I would add an 'else if' clause into the mix where you get a new value for the variable, an let the else clause display a score and break out of the loop.
if (arrayGuess === sportsArray[counter]) {
// Add to the score
} else if (counter < 2) {
// We prompted for the first guess before the loop,
// so take the second and third here
arrayGuess = prompt("Guess a sport.", "Enter Here");
} else {
// Display score then break to exit the loop
break;
}
And I'm not sure I understand the problem at all.
var vtf=[]; // Dictionary that maps number-> list
var length;
var s; // A list of numbers with s.length = length
// length and s are set to values
for(i=0; i<length; i++)
{
var f=s[i];
if(f in vtf)
vtf[f].push(i);
else
vtf[f]=[i];
}
So basically I check if vtf contains the value f=s[i]. If it does it appends i to the list contained at vtf[f] and if it doesn't it makes a new list with i as its only element.
The problem I get is that after running this every index of vtf only contains that first i that was added despite me knowing that almost every value saved in vtf should have a list of multiple elements.
I can't understand what I'm doing wrong. When I put alerts inside the if statement they don't even pop up but when I put them outside the loop, for the same value, they show it's evaluating to true a number of times.
Your code is correct, the only thing, vtf should be declared as an object, not as an array:
var vtf={};
var s=[1,2,3,4,1,2,3,4];
for(i=0; i<s.length; i++)
{
var f=s[i]; // All values in s are numbers
if(f in vtf)
vtf[f].push(i);
else
vtf[f]=[i];
}
console.log(JSON.stringify(vtf))
Result:
"{"1":[0,4],"2":[1,5],"3":[2,6],"4":[3,7]}"
I have been working on creating a custom script to help manage a secret questions form for a login page. I am trying to make all the seperate select lists dynamic, in that if a user selects a question in one, it will no longer be an option in the rest, and so on. Anyways, the problem I am having is when I try to set the variables in the other lists to null. I am currently working with only 3 lists, so I look at one list, and find/delete matches in the other 2 lists. Here is my loop for deleting any matches.
for(i=0; i<array1.length; i++) {
if(array2[i].value == txtbox1.value) {
document.questions.questions2.options[i] = null
}
if(array3[i].value == txtbox1.value) {
document.questions.questions3.options[i] = null
}
}
This works fine if both the matches are located at the same value/position in the array. But if one match is at array1[1] and the other match is at array3[7] for example, then only the first match gets deleted and not the second. Is there something I am missing? Any help is appreciated. Thanks!
I don't see too many choices here, considering that the position in each array can vary.
Do it in separate loops, unless of course you repeat values in both arrays and share the same position
EDTI I figured out a simple solution, it may work, create a function. How about a function wich recives an array as parameter.
Something like this:
function finder(var array[], var valueToFound, var question) {
for (i=0; i<array.lenght; i++) {
if (array[i].value == valueToFound) {
switch (question) {
case 1: document.questions.questions1.options[i] = null;
break;
}
return;
}
}
}
I think i make my point, perhaps it can take you in the right direction
My bet is that the code isn't getting to array3[7] because either it doesn't exist or that array2 is too short and you're getting a JavaScript exception that's stopping the code from doing the check. Is it possible that array2 and array3 are shorter than array1?
It is more code, but I would do it like this:
var selectedvalue == txtbox1.value;
for(i=0; i<array2.length; i++) { // iterate over the length of array2, not array1
if(array2[i].value == selectedvalue) {
document.questions.questions2.options[i] = null;
break; // found it, move on
}
}
for(i=0; i<array3.length; i++) {
if(array3[i].value == selectedvalue) {
document.questions.questions3.options[i] = null;
break; // you're done
}
}