I have this code which im echoing data from jquery success .
for(i = 0;i < dat.id.length; i++){
// im echoing data here
}
and i want check for the highest value in dat.voteup
like that (It works)
var maxvoteup = 0;
if (dat.voteup[i] - dat.votedown[i] ==maxvoteup) {
console.log(maxvoteup);
//i want fetch maxvoteup here
}
But i want make just one For loop not two . How can i do that pls?
EDIT:
var maxvoteup = 0;
for (i = 0;i < (dat.voteup-dat.votedown).length ;i++) {
if (dat.voteup[i] - dat.votedown[i]>maxvoteup) {
maxvoteup = dat.voteup[i] - dat.votedown[i];
console.log(maxvoteup);
//i want fetch maxvoteup here
}
}
EDIT2:
this is what im getting in my jquery response , But actually my max vote is 10 not 8 . 8 is just voted up to 8 , but there is other votes which is 10.
{"status":"success","message":[],"date_edited":[2016-04-21 21:31:25],"voteup":[],"votedown":[8],"id":[]}
Your code is a little hard to read, but if I understand correctly I believe all you need to do is combine both into a single loop with maxvoteup defined outside.
var maxvoteup = 0;
for(i = 0;i < dat.id.length; i++){
// echo data...
// max upvote
if (dat.voteup[i] - dat.votedown[i] == maxvoteup) {
console.log(maxvoteup);
}
}
EDIT:
Unfortunately getting the maximum value from a list requires you to iterate through the list, i.e., a maximum value cannot be found in constant time. I suggest you first find the maximum, and then proceed with your for loop.
Also, if you know your maximum is a list of numbers, you can actually use Javascript's apply to make the code a little cleaner:
var maxvoteup = Math.max.apply(Math, listOfMaxVotes);
See here: How does the Math.max.apply() work?
EDIT2:
If you want to continuously keep track of the maximum, then all you need to do is move the maxvoteup variable to outside of your response handlers so you can always keep track.
// global scope...
var maxvoteup = 0;
// your jquery response handler
var onSuccessData = function(data) {
// get the highest possible max from the `voteup` and `votedown` lists
var responseMax = Math.max.apply(Math, data.voteup.concat(data.votedown));
// check if it's greater than our global maxvoteup
if (responseMax > maxvoteup) {
// if it is, then update our global `maxvoteup` to the new value
maxvoteup = responseMax;
}
// continue with your other processing...
};
Related
I want to make a program in javascript in which a person inputted the iteration count for a for loop(they could input x++, or y--), but I don't know if I am using the right method.
Here is my code:
var x = prompt("iteration count")
// x should equal something like, i++, or x--
for(var i = 0; i < 10; x){
document.write(i)
}
But when the code ran the program kept crashing.
Why is it crashing and how do I fix this?
Please Help
you need to parse the int value of x because it's a string and use it to increment i
var x = parseInt(prompt("iteration count"))
for (var i = 0; i < 10; i += x) {
document.write(i)
}
EDIT :
based on the question edit and the comments, you can use eval(), but :
Do not ever use eval!
eval() is a dangerous function, which executes the code it's passed with the privileges of the caller.
So before you use it, read the MDN page and check : eval isnt evil it's just misunderstood
where there's this comment from Spudley :
From a security perspective, eval() is far more dangerous in a server
environment, where code is expected to be fully trusted and hidden
from the end user.
In a browser, the user could eval any code they wanted at any time
simply by opening dev tools, so as a developer you can't get away with
having anything on your client code that could be insecure against
eval anyway.
to test the snippet below, type i++ in the prompt
var x = prompt("iteration count");
for (var i = 0; i < 10; eval(x)) {
console.log(i)
}
an alternative to eval() would be new Function or check the answers here : Programatically setting third statement of for loop
var input = 'i++';//Or whatever condition user passing in
var conditionProgramatically = () => new Function(input)() ;
for (var i = 0; i < 10; conditionProgramatically()) {
console.log(i)
}
For for-loop, third statement will be invoked/executed on every iteration, and hence we set a function call, and in that function, we execute whatever user passing in as you've mentioned i++
That is an endless loop because the variable i never incremented. Try this one.
var x = prompt("iteration count")
for(var i = 0; i < x, i++){
document.write(i)
}
You forgot to increment the index variable, it result to endless loop and maximum stack error, you can also use + for parseInt shorcut.
var x = +prompt("iteration count")
for(var i = 0; i < x;i++){
document.write(i)
}
You have to parse the input value and then make it as a condition to stop iterating after the given value.
var x = parseInt(prompt("iteration count"))
for (var i = 0; i < x; i++) {
document.write(i);
}
I am having multiple issues with my <select> element in angular and am trying to understand what is going on. My first step is to understand why the multiple console.log() messages I have put in for debugging repeatedly appear in the console, as in, instead of the message appearing once like I would expect, they appear an infinite number of times, as if part of an infinite loop. Is this how a function called from an ng-options is supposed to behave? If so, I don't understand why, if not, then I would like to fix my loop.
My html: <select ng-options="theorderdate as theorderdate for theorderdate in getOtherOrderDates(Bread.text)" ng-model="randomDateRomantic.randomDateRomantic" ng-change="soRomantic(Bread.text)"></select>
The console.log() messages appear from the getOtherOrderDates() function, which is below (with my comments included):
$scope.getOtherOrderDates = function(loaf) {
var istheLoafdaily = false;
var theorderdates = [];
for (var i = 0; i < $scope.theBreadsList.length; i++) {
for (var z = 0; z < $scope.theBreadsList[i].breads.length; z++) {
if ($scope.theBreadsList[i].breads[z].text == loaf && i > 0) //not a daily loaf, goes beyond "Daily Breads"
{
console.log(theorderdates);
theorderdates = theorderdates.concat($scope.theBreadsList[i].breads[z].orderDates); //concat the matched bread's order dates
console.log(theorderdates, $scope.theBreadsList[i].breads[z].orderDates);
theorderdates = _.sortBy(theorderdates, function(m) {
return m.getTime()
});
for (var y = 0; y < theorderdates.length; y++) {
theorderdates[y] = theorderdates[y].toLocaleDateString();
}
theorderdates = _.uniq(theorderdates);
if (theorderdates.length > 0) {
console.log("Something is wrong here"); //problem
$scope.randomDateRomantic.randomDateRomantic = theorderdates[0];
}
console.log(theorderdates);
return theorderdates;
} else if ($scope.theBreadsList[i].breads[z].text == loaf && i == 0) { //a daily loaf, i == 0
console.log("The bread matched is daily", loaf); //***
istheLoafdaily = true;
console.log(theorderdates); //***
theorderdates = theorderdates.concat($scope.theBreadsList[i].breads[z].orderDates); // concat the matched bread's order dates
console.log(theorderdates, $scope.theBreadsList[i].breads[z].orderDates); //***
break; // escape the for loop, should it be two breaks?????? yes...
} else if (istheLoafdaily && i > 0 && $scope.theBreadsList[i].breads[z].orderDates.length > 0) { //not sure what scenario this matches, hence wtf
theorderdates = theorderdates.concat($scope.theBreadsList[i].breads[z].orderDates);
console.log("wtf");
}
}
}
//end of outermost for loop
//not sure what this is doing because this functionality is repeated up there^ (for non-daily breads)
theorderdates = _.sortBy(theorderdates, function(m) {
return m.getTime()
});
for (var y = 0; y < theorderdates.length; y++) {
theorderdates[y] = theorderdates[y].toLocaleDateString();
}
theorderdates = _.uniq(theorderdates);
if (theorderdates.length > 0) {
$scope.randomDateRomantic.randomDateRomantic = theorderdates[0];
console.log("Something is wrong here (daily)"); //problem
}
return theorderdates;
//not sure what this is doing because this functionality is repeated up there^ (for non-daily breads)
//if change to Locale date string then not unique, but if don't change then not a date to sort!!!!!!! >:(
},
I am getting almost all console messages an infinite number of times, without doing anything such as firing the ng-change function. I just add a daily bread to my cart for instance, and then the console gets filled with the following messages, that I have starred in my code.
My theBreadsList is not very long, so there is something going on that it is going repeatedly like this. Even if I broke out of the for loop twice as you will see in my code, it wouldn't explain the fact that it logs to the console all the time, because eventually the loop would not be satisfied, and this wouldn't take to long as has been mentioned.
Please advise, thank you. If you need more information, I am happy to provide.
The getOtherOrderDates will be called in each digest cycle so that angular knows whether to update options in select. That's most likely the reason you're seeing this method being called many times.
If you're worried about performance impact of this loop you can build the options upfront inside your controller store it in $scope like so:
$scope.options = $scope.getOtherOrderDates($scope.Bread.text);
whenever $scope.Bread.text changes and then use $scope.options inside your template.
To avoid triggering your loops in every digest loop you can use one time binding ::value.
<select ng-options="theorderdate as theorderdate for theorderdate in ::getOtherOrderDates(Bread.text)"
ng-model="randomDateRomantic.randomDateRomantic"
ng-change="soRomantic(Bread.text)"></select>
Thanks to that expression inside ng-options will be evaluated only once and the watcher will be removed after first evaluation which will stop your function being triggered in next digest loop iterations.
DOCS
This may not be a good question, but it does makes sense(atleast to me, it does.)
Suppose I have a multi-dimensional array called temporaryFrequency. Now, I want to write a function which will take one argument --> frequencyArray[number]. This will be more clear from the code:
JS:
function getMaxTemporaryFrequency(frequencyArray[number]){
var maxOutofThese = frequencyArray[number][0];
for(var i = 0; i < frequencyArray[number].length; i++){
if(frequencyArray[number][i] > maxOutofThese)
maxOutofThese = frequencyArray[number][i];
}
return maxOutofThese;
}
This is the function which will return the maximum frequency from a sub-array of an array. Now, I will execute the following code to call the function:
//This is to get the max out of the temporary frequencies
for(var n = 0; n < temporaryFrequency.length; n++){
var maximumTempFrequency + (n + 1) = getMaxTemporaryFrequency(temporaryFrequency[n]);
}
Now, I have one more question attached to this. Can variable names be concatenated, like a did here? For example, for each loop count, I want to make variables : maximumTempFrequency1 , maximumTempFrequency2 , maximumTempFrequency3 and so on.
Now, this call of the function passes the nth element of the temporaryFrequency array to the function, which should return the greatest value from that nth sub-array. But, that is not working.
So, to summarise my question:
1) Can we pass an array with a key to function, like I did here? If
no, is there any way to do it?
2) Can we concatenate strings to make a variable name, like I did in
the 'for' loop? If no, is there any other method
*NOTE: For this question, viewers don't need to know the contents of the temporaryFrequency array.
The straight answer to your two questions are No.
The syntax function getMaxTemporaryFrequency(frequencyArray[number]) { ... } is not valid. The parser is expecting an identifier for the parameter name, and identifiers can't have brackets in them [ or ]. This results in the error:
Uncaught SyntaxError: Unexpected token [
Similarly, your variable name is also syntactically invalid. var maximumTempFrequency + (n + 1) = //anything results in
Uncaught SyntaxError: Unexpected token +
To answer your follow up questions of How to make it work, for the first question you can pass the dereferenced array member to the function when you call it (instead of when you declare it).
var frequencyArray = []; // fill it with your values
var number = 0; // or whatever number you want
function getMaxTemporaryFrequency(arr){
var maxOutofThese = arr[0];
for(var i = 0; i < arr.length; i++){
if(arr[i] > maxOutofThese)
maxOutofThese = arr[i];
}
return maxOutofThese;
}
function getMaxTemporaryFrequency(frequencyArray[number]);
For the latter one, you want to store the results to an array, like this:
//This is to get the max out of the temporary frequencies
var maximumTempFrequency = [];
for(var n = 0; n < temporaryFrequency.length; n++){
maximumTempFrequency[n+1] = getMaxTemporaryFrequency(temporaryFrequency[n]);
}
Note that your syntax getMaxTemporaryFrequency(temporaryFrequency[n]) is an example of what I put in the first code block above.
I am working on a JS where I want to create a simple game that starts by chosing number of players, name of each player and whether a player is a dealer or not. There can be only one dealer for each game:
function player(playerName, playerDealer) {
this.playerName = playerName;
this.playerDealer = playerDealer;
}
var playerNumber = prompt('Nr of players?');
var playersArray = [];
for (i = 0; i < playerNumber; i++) {
var j = i + 1;
var dealerAssigned = false; // control variable to check whether dealer has been assigned
var inputName = prompt('Name of player nr ' + j);
var inputDealer = prompt('Is player ' + inputName + ' also a dealer? (yes/no)');
playersArray[i] = new player(inputName, inputDealer);
for (k=0;k<playerNumber;k++){ // I want to go through the players array to check if dealer has been assigned
if (playersArray[k].playerDealer == 'yes') {
dealerAssigned=true;
break;
};
};
if(dealerAssigned){ //if dealer has been assigned, don't add the current player to the array and continue with the next iteration
alert("already assigned");
continue;
};
};
I need to include a simple test into the loop that would check if the dealer has been appointed. If so, I want the script only to alert 'already assigned' and skip to the next player. But I am constantly getting the following error
TypeError: playersArray[k] is undefined
Can anybody explain why is it undefined?/What am I doing wrong?
The bug you're specifically asking about appears to me to be that you're iterating over undefined array values, as the error you're getting suggests.
You're getting the number of players you want in line
var playerNumber = prompt('Nr of players?');
Then, you proceed to have two iterations (one nested in the other), in which the inner loop is trying to access values that haven't yet been assigned since the outer loop hasn't gotten there yet:
for (i = 0; i < playerNumber; i++) {
playersArray[i] = new player(inputName, inputDealer);
for (k=0; k < playerNumber; k++) {
if (playersArray[k].playerDealer == 'yes') {
...
}
}
}
It appears to me that the logical error here is the nested loop. I recommend just initializing all players in one loop, then verify that all players have an assigned dealer afterward.
I should add that I'm being intentionally myopic here and focusing very narrowly on the question asked and overlooking other issues I see.
Your for loop inside a for loop is iterating over an array that hasn't been filled yet.
First iteration playersArray[j] = new Player(...) makes the array [Player] or an array of one element! Yet the second loop is looking for an array of many elements. once you look for playersArray[1] but there is only playerArray[0] you get undefined and so undefined.playerDealer causes a TypeError.
`This is your structure stipped-down:
for (i = 0; i < playerNumber; i++) {
playersArray[i] = new player(inputName, inputDealer);
for (k=0;k<playerNumber;k++)...{
//anything with index k > i is undefined, since your outer loop
//hasn't initialized it yet.
}
}
It seems that your i-loop is trying to insert elements for the size of the array to be, but your k-loop is trying to also access the entire array instead of just the initialized portions. Limit this to for (k=0; k<i+1 ;k++) so you only check the previously initialized values of you playersArray
This question is regarding Javascript for loops, where I've been having some weird behaviour.
My For loop currently looks like this:
var UnitAmount = 2;//(value verified, yet not declared like this)
var DamageAmount = [1,3];//(value verified, yet not declared like this)
function forcerefresh () {
for( i=0 ; i < UnitAmount ; i++ ) {
//(10 lines of Stuff)
var check = 0;
for (c = 0; c < DamageAmount[i] ; c++ ) {
debug[0] = damage[i][c].getElementsByClassName("writedamage")[0];
debug[1] = damage[i][c];
debug[2] = unit[i];
check = check + 1;
console.info("Unit:",i,"Loop:",c,"Debug:",debug,"Check:",check, "Race:",unitrace[i], unit[i].dataset.race);
alert("Debug:"+ debug );
damageCalc(damage[i][c].getElementsByClassName("writedamage")[0],damage[i][c],unit[i]);
}
}
}
In here, debug, alert, Check and the console write call are already added to attempt to find the problem - I'm getting an infinite loop here.
The output im getting in the console shows that while the i constant walks as intended, but the c Iteration count starts at 0, jumps to 2, and then stays 2 - and since the DamageAmount[1] = 3, this creates an infinite loop. And where the c might stick at value 2, the check values does walk up through the iterations.
As for the amount of variables involved, I've checked time and again with the console, and all of them are defined, and the values I expected. The Code is located at http://age-of-wonders-3.wikia.com/wiki/MediaWiki:Units.js, but if any parts are requested I'll of course post them here.
Any help is appreciated!
Try using for of or .forEach on an array