EDIT: Pete provided a really good solution that works when the fields contain numbers, however I need to be able to sort strings too - any ideas?
I'm trying to write a javascript sorting algorithm that will sort a table based on the column clicked - I know this is semi-reinventing the wheel but the design is too complex for me to try and insert some other plugin etc.
Some columns are text, some columns are numbers.
Clicking a column calls: sort(X,Y). X is the column number so we know which cells to compare for the sort. Y is the mode, i.e. ascending or descending.
The code for the sort function is:
function sort(field, mode) {
var tabrows = 0;
$(".data tr").each(function() { if($(this).hasClass("hdr")) { } else {tabrows++;} });
var swapped;
do {
swapped = false;
for (var i=0;i< tabrows; i++) {
var j = i + 3;
var k = i + 4;
var row1 = $(".data tr:nth-child("+j+")");
var row2 = $(".data tr:nth-child("+k+")");
var field1 = row1.find("td:eq("+field+")").text();
var field2 = row2.find("td:eq("+field+")").text();
if(shouldswap(field1, field2, mode)) {
swaprows(row1, row2);
swapped = true;
}
}
} while (swapped);
}
The shouldswap function is as follows:
function shouldswap(field1, field2,mode) {
if(field1 > field2) {
if(mode==1) {
return true;
} else {
return false;
}
}
return false;
}
Code for swaprows function:
function swaprows(row1, row2) {
row2.insertBefore(row1);
}
Can anyone see why this would cause the browser to freeze/lockup. I've been working on this for quite a while so I think a fresh pair of eyes may point out something silly! Any help is appreciated :)
The problem might be that you're calling the jQuery constructor a bunch of times and doing heavy operations on it (e.g. using .find() with complex selectors). Therefore, your function is just slow and that's probably the issue.
The good news is that JavaScript has a native implementation of QuickSort (a very fast sorting function) that will probably take care of your needs. When combined with a reduction in expensive calls, your code should end up being enormously more efficient. I'd change your code to look like this:
var sortByField = function(field, mode) {
var numExp = /^-?\d*\.?\d+$/;
var $rows = $(".data tr:not(.hdr)"), $table = $(".data");
$rows.each(function () {
this.fieldVal = $(this).find("td:eq("+field+")").text();
if(numExp.test(this.fieldVal)) { //if field is numeric, convert it to a number
this.fieldVal = +this.fieldVal;
}
}).sort(function (a, b) {
if (mode === 1) {
return (a.fieldVal > b.fieldVal) ? -1 : 1;
}
return (a.fieldVal < b.fieldVal) ? -1 : 1;
}).detach().each(function () {
$(this).appendTo($table);
});
};
This won't work well with multiple tables on one page (because it assumes everything is on the same table). So if you want to do that, you should pass in the table or table selector as a parameter. But that's an easy fix to make. You can see my solution in action here:
http://jsfiddle.net/r8wtK/ (updated)
It should be far more efficient than your code and should reduce "freezing" by quite a bit (ore even entirely).
UPDATE:
The OP noted that some fields may contain strings. Doing a string comparison on numbers is bad because it returns a lexicographical ordering (e.g. "10" < "2"). So I added a test to see if the data appear to be numeric before doing the sort.
Could it be that you're adding 3 and 4 to i in order to get your row indices? So when i gets to (tabrows-1), it appears that it will be trying to access rows with index of (tabrows+2) and (tabrows+3). If I understand your logic correctly, these are out of bounds, so row1, row2, field1 and field2 will be empty. Therefore, if you're in mode==1, I think this will make it so that your algorithm attempts to swap these two non-existent rows and keeps comparing for infinity. Does this make sense, or am I misunderstanding your logic?
If that's the case, I think you just need to change your for loop to:
for (var i=0;i< tabrows-4; i++) {
// your code
}
What is the purpose of adding 3 to j and 4 to k anyway? Do you have 3 rows of data at the top that you don't want to compare?
Related
I want to check that a range of cell are empty or has any values in them, I use this for loop :
for (let i = 0; i <= namesRange.getCellCount(); i++) {
if (namesRange.getCell(i,0).getText() == "")
{
break;
}
bookedCount += 1;
}
However this iteration is extremely slow (as is the use of Range.getValue, but the console warns you that iterating with .getValue is slow, does not warn you with getText) It takes several seconds to iterate over a very short list of 10 elements.
Is there any way to check for the values of a cell in a speedy manner using ExcelScripts?
Does this mean that, even if I develop a UDF or a ribbon Add-In with office.js and Node.js it will also be this extremely slow for iterating over cells?
Is there any way to make this faster?
The reason your code is likely performing slowly is that the calls to getCell() and getText() are expensive. Instead of performing these calls every time in the loop you can try a different approach. One approach is to get an array of the cell values and iterate over that. You can use your namesRange variable to get the array of values. And you can also use it to get the row count and the column count for the range. Using this information, you should be able to write nested for loops to iterate over the array. Here's an example of how you might do that:
function main(workbook: ExcelScript.Workbook) {
let namesRange: ExcelScript.Range = workbook.getActiveWorksheet().getRange("A1");
let rowCount: number = namesRange.getRowCount();
let colCount: number = namesRange.getColumnCount();
let vals: string[][] = namesRange.getValues() as string[][];
for (let i = 0; i < rowCount; i++) {
for (let j = 0; j < colCount; j++) {
if (vals[i][j] == "") {
//additional code here
}
}
}
}
Another alternative to the first answer is to use the forEach approach for every cell in the range of values.
It can cut down the amount of variables you need to achieve the desired result.
function main(workbook: ExcelScript.Workbook)
{
let worksheet = workbook.getActiveWorksheet();
let usedRange = worksheet.getUsedRange().getValues();
usedRange.forEach(row => {
row.forEach(cellValue => {
console.log(cellValue);
});
});
}
I have seen several answers on Stackoverflow but none have helped me. I have a huge array of nearly 100,000 words, of which I am trying to remove all words that contain a number. I am using the following to do that:
for(var i = 0; i < words.length; i++){
if (hasNumbers(words[i]) {
words.splice(i, 1);
}
function hasNumbers(t)
{ return /\d/.test(t); }
It seems to work, but not all the time because I am still getting words that contain numbers. What can I change to make this remove all words that contain any number at all?
(I am using p5.js with my js)
That is because when you delete a word at index i, the next word will have index i, yet you still increase i, thereby skipping a word which you never inspect.
To solve this you can go backwards through your array:
for(var i = words.length - 1; i >= 0; i--){
// etc.
Here is a shorter way to remove words with digits:
words = words.filter(a => !hasNumbers(a));
Finally, you really should call your second function hasDigits instead of hasNumbers. The words "digit" and "number" have a slightly different meaning.
Here is a snippet, using ES6 syntax, that defines the opposite function hasNoDigits and applies it to some sample data:
let words = ['abcd', 'ab0d', '4444', '-)#', '&9ยต*'];
let hasNoDigits = s => /^\D*$/.test(s);
console.log(words.filter(hasNoDigits));
words = words.filter(a => !hasNumbers(a));
I had started writing this and then trincot answered. His answer is correct, though with the popular and widespread usage of ES5 array functions, I feel like you could simplify this down quite a bit.
window.addEventListener('load', function() {
var data = [
'w3.org',
'google.com',
'00011118.com'
]; //This is supposed to be your data, I didn't have it so I made it up.
var no_nums = data.filter(function(item) {
//Tests each string against the regex, inverts the value (false becomes true, true becomes false)
return !/\d/.test(item);
});
var results = document.getElementById('results');
no_nums.forEach(function(item) {
results.innerHTML += item + '<br />';
//Loops through each of our new array to add the item so we can see it.
});
});
<div id="results">
</div>
I am writing some code, that is supposed to automatically filter a Tableau workbook, based on the values of an array.
The function is called through:
showOnly2('Disponent',filterString);
'Disponent' is hard coded, filterString is an array of this format:
['201','202','203','204','205','206','207','208','209']
In the following block of code:
function showOnly2(filterName, values) {
document.getElementById("header").innerHTML = values;
sheet = viz.getWorkbook().getActiveSheet();
if(sheet.getSheetType() === 'worksheet') {
sheet.applyFilterAsync(filterName, values, 'REPLACE');
} else {
worksheetArray = sheet.getWorksheets();
for(var i = 0; i < worksheetArray.length; i++) {
worksheetArray[i].applyFilterAsync(filterName, values, 'REPLACE');
}
}
}
The worksheetArray[i].applyFilterAsync(filterName, values, 'REPLACE'); part does not work when called with the variable "values".
However, if I hard-code the value of the array into the formula:
worksheetArray[i].applyFilterAsync(filterName, ['201','202','203','204','205','206','207','208','209'] , 'REPLACE');
it works like a charm...Unfortunately I cannot hard-code it, as the numbers in the array (the filter values I want to set), change over time.
Does anybody have an idea, why the variable version does not work?
(I also checked for scope issues, by implementing document.getElementById("header").innerHTML = values;
within the function, just to doublecheck that the array value is read properly.
Any pointers are much appreciated.
The answer is straight forward.
The API expectes an array-object not a string (although when displayed as a string both look the same).
Hence, the following code worked flawlessly:
var filterArray = [];
for(var i = 201; i < 300; i++) {
filterArray.push(i);
}
I have a big question.
I have many Strings in my Programm and want to check these Strings on there values.
I wrote a Loop for it, but insted of the Definition of an String he is creating a new value. It's basicly really difficult to discribe, also because i am basicly German.
But i can give you my current code, so maybee you will see what I mean:
{
var Loch1G = $('#m1-Rundenanalyse-Datum').val(); //In the strings just the number is changing
var Loch2G = $('#m1-Rundenanalyse-Turnier').val();
x=1
while (x <= 2) {
if ("Loch" + x + "G" == ""){ //Next String is genrated (x=x+1)
alert("Eingabe war leer");
}
x=x+1
}
}
How can I solve this?
I'd suggest using an array to store the values you want to check:
var lochs = [];
lochs.push($('#m1-Rundenanalyse-Datum').val());
lochs.push($('#m1-Rundenanalyse-Turnier').val());
for (var i = 0, len = lochs.length; i < len; i++){
if (lochs[i] == ''){
alert("Eingabe war leer");
}
}
JS Fiddle demos: passes (no alert), fails (alert)
This suggestion is based on my presumption that you're trying to create the names of the vars you want to check, which won't work, whereas this approach lets you store all values (however many) in the same array and then iterate over that array to find any values that are equal to an empty string.
If you really want to stick with your current approach, you could do the following:
{
window.Loch1G = $('#m1-Rundenanalyse-Datum').val(); //In the strings just the number is changing
window.Loch2G = $('#m1-Rundenanalyse-Turnier').val();
var x=1;
while (x <= 2) {
if (window["Loch" + x + "G"] == ""){ //Next String is genrated (x=x+1)
alert("Eingabe war leer");
}
x=x+1;
}
}
But I can't think why you'd want to; plus the use of global variables is poor practice as it explicitly makes those variables available to every closure within the document, which allows them to be easily, and accidentally, overwritten.
In a reasonably up-to-date browser, that implements Array.prototype.every, you could dispense with the explicit iteration:
var lochs = [];
lochs.push($('#m1-Rundenanalyse-Datum').val());
lochs.push($('#m1-Rundenanalyse-Turnier').val());
if (!lochs.every(function(a){ return a !== ''; })) {
alert("Eingabe war leer");
}
JS Fiddle demos: passes (no alert), fails (alerts).
Situation
I'm currently writing a javascript widget that displays a random quote into a html element. the quotes are stored in a javascript array as well as how many times they've been displayed into the html element. A quote to be displayed cannot be the same quote as was previously displayed. Furthermore the chance for a quote to be selected is based on it's previous occurences in the html element. ( less occurrences should result in a higher chance compared to the other quotes to be selected for display.
Current solution
I've currently made it work ( with my severely lacking javascript knowledge ) by using a lot of looping through various arrays. while this currently works ( !! ) I find this solution rather expensive for what I want to achieve.
What I'm looking for
Alternative methods of removing an array element from an array, currently looping through the entire array to find the element I want removed and copy all other elements into a new array
Alternative method of calculating and selecting a element from an array based on it's occurence
Anything else you notice I should / could do different while still enforcing the stated business rules under Situation
The Code
var quoteElement = $("div#Quotes > q"),
quotes = [[" AAAAAAAAAAAA ", 1],
[" BBBBBBBBBBBB ", 1],
[" CCCCCCCCCCCC ", 1],
[" DDDDDDDDDDDD ", 1]],
fadeTimer = 600,
displayNewQuote = function () {
var currentQuote = quoteElement.text();
var eligibleQuotes = new Array();
var exclusionFound = false;
for (var i = 0; i < quotes.length; i++) {
var iteratedQuote = quotes[i];
if (exclusionFound === false) {
if (currentQuote == iteratedQuote[0].toString())
exclusionFound = true;
else
eligibleQuotes.push(iteratedQuote);
} else
eligibleQuotes.push(iteratedQuote);
}
eligibleQuotes.sort( function (current, next) {
return current[1] - next[1];
} );
var calculatePoint = eligibleQuotes[0][1];
var occurenceRelation = new Array();
var relationSum = 0;
for (var i = 0; i < eligibleQuotes.length; i++) {
if (i == 0)
occurenceRelation[i] = 1 / ((calculatePoint / calculatePoint) + (calculatePoint / eligibleQuotes[i+1][1]));
else
occurenceRelation[i] = occurenceRelation[0] * (calculatePoint / eligibleQuotes[i][1]);
relationSum = relationSum + (occurenceRelation[i] * 100);
}
var generatedNumber = Math.floor(relationSum * Math.random());
var newQuote;
for (var i = 0; i < occurenceRelation.length; i++) {
if (occurenceRelation[i] <= generatedNumber) {
newQuote = eligibleQuotes[i][0].toString();
i = occurenceRelation.length;
}
}
for (var i = 0; i < quotes.length; i++) {
var iteratedQuote = quotes[i][0].toString();
if (iteratedQuote == newQuote) {
quotes[i][1]++;
i = quotes.length;
}
}
quoteElement.stop(true, true)
.fadeOut(fadeTimer);
setTimeout( function () {
quoteElement.html(newQuote)
.fadeIn(fadeTimer);
}, fadeTimer);
}
if (quotes.length > 1)
setInterval(displayNewQuote, 10000);
Alternatives considered
Always chose the array element with the lowest occurence.
Decided against this as this would / could possibly reveal a too obvious pattern in the animation
combine several for loops to reduce the workload
Decided against this as this would make the code to esoteric, I'd probably wouldn't understand the code anymore next week
jsFiddle reference
http://jsfiddle.net/P5rk3/
Update
Rewrote my function with the techniques mentioned, while I fear that these techniques still loop through the entire array to find it's requirements, at least my code looks cleaner : )
References used after reading the answers here:
http://www.tutorialspoint.com/javascript/array_map.htm
http://www.tutorialspoint.com/javascript/array_filter.htm
http://api.jquery.com/jQuery.each/
I suggest array functions that are mostly supported (and easily added if not):
[].splice(index, howManyToDelete); // you can alternatively add extra parameters to slot into the place of deletion
[].indexOf(elementToSearchFor);
[].filter(function(){});
Other useful functions include forEach and map.
I agree that combining all the work into one giant loop is ugly (and not always possible), and you gain little by doing it, so readability is definitely the winner. Although you shouldn't need too many loops with these array functions.
The answer that you want:
Create an integer array that stores the number of uses of every quote. Also, a global variable Tot with the total number of quotes already used (i.e., the sum of that integer array). Find also Mean, as Tot / number of quotes.
Chose a random number between 0 and Tot - 1.
For each quote, add Mean * 2 - the number of uses(*1). When you get that that value has exceeded the random number generated, select that quote.
In case that quote is the one currently displayed, either select the next or the previous quote or just repeat the process.
The real answer:
Use a random quote, at the very maximum repeat if the quote is duplicated. The data usages are going to be lost when the user reloads/leaves the page. And, no matter how cleverly have you chosen them, most users do not care.
(*1) Check for limits, i.e. that the first or last quota will be eligible with this formula.
Alternative methods of removing an array element from an array
With ES5's Array.filter() method:
Array.prototype.without = function(v) {
return this.filter(function(x) {
return v !== x;
});
};
given an array a, a.without(v) will return a copy of a without the element v in it.
less occurrences should result in a higher chance compared to the other quotes to be selected for display
You shouldn't mess with chance - as my mathematician other-half says, "chance doesn't have a memory".
What you're suggesting is akin to the idea that numbers in the lottery that haven't come up yet must be "overdue" and therefore more likely to appear. It simply isn't true.
You can write functions that explicitly define what you're trying to do with the loop.
Your first loop is a filter.
Your second loop is a map + some side effect.
I don't know about the other loops, they're weird :P
A filter is something like:
function filter(array, condition) {
var i = 0, new_array = [];
for (; i < array.length; i += 1) {
if (condition(array[i], i)) {
new_array.push(array[i]);
}
}
return new_array;
}
var numbers = [1,2,3,4,5,6,7,8,9];
var even_numbers = filter(numbers, function (number, index) {
return number % 2 === 0;
});
alert(even_numbers); // [2,4,6,8]
You can't avoid the loop, but you can add more semantics to the code by making a function that explains what you're doing.
If, for some reason, you are not comfortable with splice or filter methods, there is a nice (outdated, but still working) method by John Resig: http://ejohn.org/blog/javascript-array-remove/