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Function to check if parameter is still the same

I have a loop that has a function inside. my target here is to check if the current data inside the loop are still the same for example my array is like this
var data = ['test1','test1','test1','test2'];
now I will check them if the data on that array inside the loop are currently the same. for example like this.
for (var i = 0; i < data.length; i++) {
var value = data[i][0];
console.log(checkifcurrent(value));
}
my problem here is to return checkifcurrent(value) if it still the same like this
function checkifcurrent(value) {
if (currentvalue is still the same as the last one) {
console.log(same);
} else {
console.log(not same);
}
}
I hope you understand tysm for understanding

You can do it like this, no need for a function call.
var data = ['test1','test1','test1','test2'];
lastValue = data[0];
for (var i = 1; i < data.length; i++) {
var currentValue = data[i];
if(lastValue==currentValue){
console.log("Value is same")
}
else
{
console.log("Value is not same")
}
lastValue = currentValue;
}

you can iterate over the data array and compare with all the array elements except the one at the current position.
If it is equals to the current and the index is not the same of the current then it is a duplicate
var data = ['test1','test1','test1','test2'];
for (var i = 0; i < data.length; i++) {
var value = data[i];
for(var j = 0; j < data.length; j++){
//skip the index at position i, because it is the one we are currently comparing
if(i !== j && data[j] === value) {
console.log('another value like: ' + value + ' at position: ' + i + ' has been found at index: ' + j)
}
}
}

Its not very clear about your task, i hope it is checking if the a value present in arr1 is available are not in arr2. If you so,
Loop through all elements in arr1 and check the indexof it
arr1 =[1,2,3,4];
arr2 = [2,3,4,5,6,6];
arr1.forEach((x)=>{if(arr2.indexOf(x)==-1){console.log('unable to find the element'+x)}})
unable to find the element1

var isSame = (function () {
var previous;
return function(value){
var result = value === previous;
previous = value;
return result;
}
})();

Alternatively you can use lodash difference function to compare old and new array.
http://devdocs.io/lodash~4/index#difference
For example:
const _ = require('lodash')
// Save the old array somewhere
let oldArray = ['test1','test1','test1','test2']
let newArray = ['test1','test1','test1','test3']
const areParametersTheSame = !!(_.difference(oldArray, newArray))

Calling all possible arrays from the length of another array

What I'm working on is a menu that auto updates its entries based on an array length. It adds groups of 10 objects' properties (in this case "IDnumbers") to the menu if a new object is added to the array.
var arraysOfObject = [], obj = {"IDNumber": ""};
for(i = 0; i<42; i++){
arraysOfObject.push({"IDNumber": "Number " + i});}
Above is the array holding 42 objects with a specific property.
var array2 = [];
var leftOver = arraysOfObject.length % 10;
var groupsOfTen = (arraysOfObject.length - leftOver)/10;
for (var i = 0; i < groupsOfTen; i++) {
array2.push([]);
for (var j = i*10; j < i*10 + 10; j++)
array2[i].push(arraysOfObject[j]["IDNumber"]);
}
//now the leftover
if (leftOver > 0) {
array2.push([]);
for (var i = groupsOfTen*10; i < arraysOfObject.length; i++)
array2[array2.length-1].push(arraysOfObject[i]["IDNumber"]);
}
The array2 above is the array that stores all the possible arrays that can be grouped by 10 from arraysOfObject. In this case there are 5 inside of it, because 4 arrays holds 40 objects, and 1 array holds the 2 remainders.
That all works fine, but placing the array2 inside the menu displays all possible IDnumbers grouped together, but not grouped individually. I have to declare each possible array inside of it like so sets = [array2[0], array2[1], array2[2], array2[3], array2[4]]; If there's a 6th possible array because object #51 has been added to arraysOfObject, I have to input it with array2[5].
I don't want it to depend on my input, but that it knows the number of possible arrays and that it displays it automatically in sets. How do I do that?
var gui = new dat.GUI();
var guiData = function() {
this.message = "Dat.Gui menu";
this.system = 0;
this.Sets = 0;
};
var data = new guiData();
sets = [array2[0], array2[1], array2[2], array2[3], array2[4], array2[5]];
gui.add(data, 'message', 'Dat.Gui Menu!');
gui.add(data, 'system', {
"1": 0,
"2": 1,
"3": 2,
"4": 3,
"5": 4,
"6": 5,
}).name('system #').onChange(function(value) {
updateSets(value);
});
gui.add(data, 'Sets', sets[0]).onChange();
function updateSets(id) {
var controller = gui.__controllers[2];
controller.remove();
gui.add(data, 'Sets', sets[id]).onChange();
data.Sets = 0;
gui.__controllers[2].updateDisplay();
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/dat-gui/0.6.1/dat.gui.min.js"></script>
<script>
var arraysOfObject = [], obj = {"IDNumber": ""};
for(i = 0; i<42; i++){
arraysOfObject.push({"IDNumber": "Number " + i});}
var array2 = [];
var leftOver = arraysOfObject.length % 10;
var groupsOfTen = (arraysOfObject.length - leftOver)/10;
for (var i = 0; i < groupsOfTen; i++) {
array2.push([]);
for (var j = i*10; j < i*10 + 10; j++)
array2[i].push(arraysOfObject[j]["IDNumber"]);
}
//now take care of the leftover
if (leftOver > 0) {
array2.push([]);
for (var i = groupsOfTen*10; i < arraysOfObject.length; i++)
array2[array2.length-1].push(arraysOfObject[i]["IDNumber"]);
}
</script>

Not the issue at hand, but I was playing around with the dat.gui as you posted it and was wondering if the dropdown could be refilled without removing/adding/etc. It seems to work with .options. (NB The initialization code makes heavy use of ES6, but can work without. The system menu is created dynamically from the sets array)
let arraysOfObject =Array.from({length:42}, (o,i) => "Number " + i),
ch =10, sets = Array.from({length:Math.ceil(arraysOfObject.length/ch)}, (a,i) => arraysOfObject.slice(i*=ch, i+ch));
var gui = new dat.GUI();
var guiData = function() {
this.message = "Dat.Gui menu";
this.system = 0;
this.Sets = 0;
};
var data = new guiData();
gui.add(data, 'message', 'Dat.Gui Menu!');
gui.add(data, 'system', sets.reduce((obj,s,i) => (obj[i+1] = i, obj), {})).name('system #').onChange(updateSets);
let controller = gui.add(data, 'Sets');
updateSets(0);
function updateSets(id) {
controller = controller.options(sets[data.Sets = id]);
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/dat-gui/0.6.1/dat.gui.min.js"></script>

I think the easiest solution would be to use ES2015's spread operator which I don't know if you would want to use yet...
ES2015 method (demo)
sets = [...array2];
There are a few other changes in the demo to set the system variable
But after taking a closer look, you can optimize the code by using the method from this SO answer to chunk your array using slice(). Also, I'm not sure why an object was used to create array entries when it just ends up as a string... demo
var arraysOfObject = [],
system = {},
chunk = 10,
size = 92;
for (var i = 0; i < size; i++) {
arraysOfObject.push("Number " + i);
}
var sets = [];
var index = 0;
for (i = 0; i < size; i += chunk) {
sets.push(arraysOfObject.slice(i, i + chunk));
system[index + 1] = index++;
}
var gui = new dat.GUI();
var guiData = function() {
this.message = "Dat.Gui menu";
this.system = 0;
this.Sets = 0;
};
var data = new guiData();
gui.add(data, 'message', 'Dat.Gui Menu!');
gui
.add(data, 'system', system)
.name('system #')
.onChange(function(value) {
updateSets(value);
});
gui.add(data, 'Sets', sets[0]).onChange();
function updateSets(id) {
var controller = gui.__controllers[2];
controller.remove();
gui.add(data, 'Sets', sets[id]).onChange();
data.Sets = 0;
gui.__controllers[2].updateDisplay();
}

Javascript. access property by string

I have a function that takes two lists(each item in the two lists are the same type). It only adds item from the second list to the first list if the item in the second list does not exist in the first list. To determine if it exist in the list, I compare the property pk.
addUniqueItemsToList: function (sourceList, toAddList) {
for (var a = 0; a < toAddList.length; a++) {
var doesItemExist = false;
for (var b = 0; b < sourceList.length; b++) {
if (sourceList[b].pk == toAddList[a].pk) {
doesItemExist = true;
break;
}
}
if (!doesItemExist) {
sourceList.push(toAddList[a]);
}
}
}
Is there a way in javascript where instead of comparing pk, I can compare it to other properties of the object, by passing in the name of the property to the function? i.e., addUniqueItemsToList: function (sourceList, toAddList, propertyName)

Yes you can compare by object property directly and access properties dinamically using string as key ej array['mykey']. Also it would be better if instead of doing a for inside a for (1for - n for) create a map in order to avoid so much iterations:
Eg: Number iterations without a map when items.length = 100 & anotherItems.length = 200
100*200 = 20000 possibles iterations.
Eg. Number of iterations creating a map with items.length = 100 & anotherItems.length = 200
300 iterations.
Example of how i do it:
var items = [{_id: 1, text: "Text 1"}, {_id:2, text: "Text 2"}];
var anotherItems = [{_id: 1, text: "Text 1"}];
var mapByProperty = function(array, prop) {
var map = [];
for (var i = 0, len = array.length; i !== len; i++) {
map[array[i][prop]] = array[i];
}
return map;
};
var commonUniqueProperty = '_id';
var mappedAnotherItemsById = mapByProperty(anotherItems, commonUniqueProperty);
for(var i = 0, len = items.length; i !== len; i++) {
if(mappedAnotherItemsById[items[i][commonUniqueProperty]]) {
console.log(items[i]);
}
}

Looping through an array to create an object in Javascript

I want to write a function that takes an array such as:
var columns = ['distance', 'times', 'acceleration']
Then from this array, I want to generate something like this:
[{id: id_0, distance: 0, times: 0, acceleration: 0}, {id: id_1, distance: 1, times: 1, acceleration: 1}]
Notice that we have 2 objects here, but I want it to be whatever number I pass in to my parameter. Here is what I have:
generateData: function(rows, columns) {
var generatedData = [];
for (var i = 0, rowLen = rows.length; i < rowLen; i++) {
for (var n = 0; i < columns.length; n++) {
// not sure how to construct an object here from looping through my columns array
generatedData.push({
id: 'id_ + n',
// confused here
});
}
return generatedData;
}
}

This is the perfect place to dynamically create your own function. Try this:
function createArrayOfObjects(columns, count) {
var objectProps = new Array(columns.length);
for (var i = 0; i < columns.length; i++){
//":j" will be the variable j inside the dynamic function
objectProps[i] = columns[i] + ":j";
}
var funcBody = "var arr = new Array(count);" +
"for(var j = 0; j < count; j++){" +
"arr[j] = {" + objectProps.join(',') + "};" +
"}" +
"return arr;";
//Create a new function and call it with count as the parameter, returning the results
return new Function("count", funcBody)(count);
}
var count = 10;
var columns = ['distance', 'times', 'acceleration'];
createArrayOfObjects(columns.concat('id'), count);
This has the benefit of only having to loop over the columns array once where other solutions require nested loops.
JSPerf

I am giving you away the initial non-optimized solution. Its upto you to do the optimizations.
generateData: function(rows, columns) {
var generatedData = [];
for (var i = 0; i < rows.length; i++) {
var myObj = {};
myObj["id_" + i] = i;
for (var n = 0; n < columns.length; n++) {
myObj[columns[n]] = i;
}
generatedData.push(myObj);
}
return generatedData;
}

A functional approach that will take the object properties from the passed in array, instead of hard-coding them, might look something like this inside the for loop to populate an array named 'rows' with property names coming from the values of an array named 'cols':
cols.forEach(function(cv, ci, ca) { rows[ri][cv] = ri; });
See the snippet for a full example. Note that, in this example, I'm just shoving the current index of "rows" into the object as the property value.
var columns = ['distance', 'times', 'acceleration'];
function generateData(numRows, cols) {
rows = new Array(numRows);
for(ri=0; ri < rows.length; ri++) {
rows[ri] = { id: ri };
cols.forEach(function(cv, ci, ca) {
rows[ri][cv] = ri;
});
}
return rows;
}
data = generateData(5, columns);
console.log(data);

How to show a list or array into a tree structure in javascript?

I pass this list from python to javascript like this:
var string=["test_data/new_directory/ok.txt","test_data/reads_1.fq","test_data/test_ref.fa"];
I want output like this:
test_data
reads_1.fq
test_ref.fa
new_directory
ok.txt
Or also the output could be like this:
test_data
reads_1.fq
test_ref.fa
test_data/new_directory
ok.txt
I used split function to get a list with each file and directory like this:
var string=["test_data/new_directory/ok.txt","test_data/reads_1.fq","test_data/test_ref.fa"];
for(var i=0;i<string.length;i++){
var result = string[i].split('/');
console.log(result);
}
Output looks like this:
["test_data", "new_directory", "ok.txt"]
["test_data", "reads_1.fq"]
["test_data", "test_ref.fa"]
How can I convert into the format I showed above? Thanks

Sorry for being late to the party. I ran into a similar issue trying to break out a list of paths into a nested object. Here's a fiddle showing how I ended up doing it.
var list = [];
list.push("A/B/C");
list.push("A/B/D");
list.push("A/B/C");
list.push("B/D/E");
list.push("D/B/E");
list.push("A/D/C");
var data = [];
for(var i = 0 ; i< list.length; i++)
{
buildTree(list[i].split('/'),data);
}
debugger;
function buildTree(parts,treeNode) {
if(parts.length === 0)
{
return;
}
for(var i = 0 ; i < treeNode.length; i++)
{
if(parts[0] == treeNode[i].text)
{
buildTree(parts.splice(1,parts.length),treeNode[i].children);
return;
}
}
var newNode = {'text': parts[0] ,'children':[]};
treeNode.push(newNode);
buildTree(parts.splice(1,parts.length),newNode.children);
}
https://jsfiddle.net/z07q8omt/

That's certainly possible, but it requires recursion.
The first thing you'll want to do (as you've already figured out to do, in fact) is split on the slashes. We'll use map for simplicity:
paths = paths.map(function(path) { return path.split('/'); });
Now we'll want to convert this into an array of objects with name and children properties. This means we'll have to use recursion.
In this function, we'll do a first pass grouping them by their first element:
var items = [];
for(var i = 0, l = paths.length; i < l; i++) {
var path = paths[i];
var name = path[0];
var rest = path.slice(1);
var item = null;
for(var j = 0, m = items.length; j < m; j++) {
if(items[j].name === name) {
item = items[j];
break;
}
}
if(item === null) {
item = {name: name, children: []};
items.push(item);
}
if(rest.length > 0) {
item.children.push(rest);
}
}
Then we can recurse on all of these (assuming the function name we chose was structurize):
for(i = 0, l = items.length; i < l; i++) {
item = items[i];
item.children = structurize(item.children);
}
Now we've got a nice structure. We can then stringify it, again with a recursive function. Since the directory listing is just each item name followed by the indented directory contents listing, we can write that fairly easily:
function stringify(items) {
var lines = [];
for(var i = 0, l = items.length; i < l; i++) {
var item = items[i];
lines.push(item.name);
var subLines = stringify(item.children);
for(var j = 0, m = subLines.length; j < m; j++) {
lines.push(" " + subLines[j]);
}
}
return lines;
}
Then, to actually do it:
console.log(stringify(structurize(paths)).join("\n"));