JS Object Array Pagination - javascript

i need some help manipulating/paginating a JS array object by 5:
var musicItems = [
["assets/audio/1.wav"],
["assets/audio/2.wav"],
["assets/audio/3.wav"],
["assets/audio/4.wav"],
["assets/audio/5.wav"],
["assets/audio/6.wav"],
["assets/audio/7.wav"],
["assets/audio/8.wav"],
];
I want to know in JS the number of sets (2) and which elements belong to which set (set1->1-5, set2->6-8). Appreciate any help.
EDIT
I am looking to do something like Split array into chunks
But as you can see, my array is different.

This is just a simple demo on how you could achieve this with the modulo operator %. There will be more efficient and smaller solutions.
var musicItems = [
["assets/audio/1.wav"],
["assets/audio/2.wav"],
["assets/audio/3.wav"],
["assets/audio/4.wav"],
["assets/audio/5.wav"],
["assets/audio/6.wav"],
["assets/audio/7.wav"],
["assets/audio/8.wav"],
];
var sets = new Object();
var set = new Array();
var setCounter = 0;
for(var i = 0; i < musicItems.length; i++) {
set.push(musicItems[i]);
if((i + 1) % 5 == 0 || (i + 1) >= musicItems.length) {
setCounter++;
sets['set' + setCounter] = set;
set = new Array();
}
}
console.log(sets['set1']);
console.log(sets['set2']);
Basically what this does is to iterate through the musicItems, with modulo % 5 we check if the current item can be devided by 5 without rest, so we know a set is complete as we collected 5 items. Then we add the set to the overall sets object to use it later on as a dictionary (as wished with 'set1', 'set2' etc.) and we clear the current set, to fill it with the next n-5 items.

Bref :
max=5,j=0;
for(var i=0;i<musicItems.length;i=i+max){
j++;
sets['set' + j] = musicItems.offset(i).max(max);
}
Explanation
Pagination concept rely on two parameters:
Offset :
Max :
Then :
musicItems.offset(0).max(5) ; // 1st set
// > [ ["assets/audio/1.wav"],["assets/audio/2.wav"],["assets/audio/3.wav"],["assets/audio/4.wav"],["assets/audio/5.wav"] ]
musicItems.offset(0+5).max(5) ; // second set
// > [ ["assets/audio/6.wav"],["assets/audio/7.wav"],["assets/audio/8.wav"] ]
Required API :
Array.prototype.max = function(mx) {
return this.filter(function(e,i){return i < mx;}); }
};
Array.prototype.offset=function(os){
return this.filter(function(e,i){return i> os-1 });
};

Related

How to set value in array depending on previous value of array

I've got a simple problem, but I'm struggling to find the easiest solution without transforming the array a hundred times.
I want to do a simple stacked graph in google sheets, with weeks on X and values on Y. I got the values for each week, but only for weeks, that have a value.
The values are all calculations I've done with google apps script/ js.
person1 = [[2019/37,2], [2019/42,3]] and so on, for multiple persons and for 80 weeks in total.
The num value is the total value after each week. So I want the array to be filled up with the missing weeks. Therefore I mapped this to another array, where I have all the weeks but no values, giving these weeks the value 0:
person1= [[2019/37,2],[2019/38,0],[2019/39,0],...,[2019/42,3],[2019/43,0],[2019/44,0],...]
This of course does not fit to see a progress in the graph.
So I need something to set the weeks, which were filled up, to the previous value, resulting in
person1= [[2019/37,2],[2019/38,2],[2019/39,2],...,[2019/42,3],[2019/43,3],[2019/44,3],...]
Looping through this and setting the values with something like person[i][1] == person[i-1][1] seems not to be a good practice of course.
So, what would be the best way to achieve this? I'm kind of stuck with this now, I feel like I don't see the forest for the trees.
Thanks in advance!
code:
let valueArray = [[2019/37,2], [2019/42,3]]
let weeksArray = [2019/38,2019/39,2019/40,2019/41...]
//find missing weeks
let notFound = weeksArray.filter(el => valueArray.includes(el) == false).map(x => [x,0]);
//concat and sort
let outArray = arr.concat(notFound).sort((a,b)=> a[0].localeCompare(b[0]));
//output:
//[[2019/37,2],[2019/38,0],[2019/39,0],...,[2019/42,3],[2019/43,0],[2019/44,0],...]
Solution:
Since you already have the expanded array, you can use map on the whole array and use a function to replace the values:
var weeks = [[2019/37,2],[2019/38,0],[2019/39,0],[2019/40,3],[2019/41,0],[2019/42,4],[2019/43,0],[2019/44,0]];
weeks.map((a,b)=>{weeks[b][1] = (a[1] == 0 && b > 0) ? weeks[b-1][1] : weeks[b][1]});
To make it more readable, this is the same as:
weeks.forEach(function missing(item,index,arr) {
if (item[1] == 0 && index > 0) {
arr[index][1] = arr[index-1][1];
}
}
);
Console log:
References:
Arrow Functions
Conditional Operator
Array.prototype.map()
function fixArray() {
var array = [["2019/1", "1"], ["2019/10", "2"], ["2019/20", "3"], ["2019/30", "4"], ["2019/40", "5"]];
var oA = [];
array.forEach(function (r, i) {
oA.push(r);
let t1 = r[0].split('/');
let diff;
if (i + 1 < array.length) {
let inc = 1;
let t2 = array[i + 1][0].split('/');
if (t1[0] == t2[0] && t2[1] - t1[1] > 1) {
do {
let t3 = ['', ''];
t3[0] = t1[0] + '/' + Number(parseInt(t1[1]) + inc);
t3[1] = r[1];
diff = t2[1] - t1[1] - inc;
oA.push(t3);
inc++;
} while (diff > 1);
}
}
});
let end = "is near";
console.log(JSON.stringify(oA));
}
console.log:
[["2019/1","1"],["2019/2","1"],["2019/3","1"],["2019/4","1"],["2019/5","1"],["2019/6","1"],["2019/7","1"],["2019/8","1"],["2019/9","1"],["2019/10","2"],["2019/11","2"],["2019/12","2"],["2019/13","2"],["2019/14","2"],["2019/15","2"],["2019/16","2"],["2019/17","2"],["2019/18","2"],["2019/19","2"],["2019/20","3"],["2019/21","3"],["2019/22","3"],["2019/23","3"],["2019/24","3"],["2019/25","3"],["2019/26","3"],["2019/27","3"],["2019/28","3"],["2019/29","3"],["2019/30","4"],["2019/31","4"],["2019/32","4"],["2019/33","4"],["2019/34","4"],["2019/35","4"],["2019/36","4"],["2019/37","4"],["2019/38","4"],["2019/39","4"],["2019/40","5"]]

How do I check if 2 numbers are the same from Math.random [duplicate]

Can't seem to find an answer to this, say I have this:
setInterval(function() {
m = Math.floor(Math.random()*7);
$('.foo:nth-of-type('+m+')').fadeIn(300);
}, 300);
How do I make it so that random number doesn't repeat itself. For example if the random number is 2, I don't want 2 to come out again.
There are a number of ways you could achieve this.
Solution A:
If the range of numbers isn't large (let's say less than 10), you could just keep track of the numbers you've already generated. Then if you generate a duplicate, discard it and generate another number.
Solution B:
Pre-generate the random numbers, store them into an array and then go through the array. You could accomplish this by taking the numbers 1,2,...,n and then shuffle them.
shuffle = function(o) {
for(var j, x, i = o.length; i; j = parseInt(Math.random() * i), x = o[--i], o[i] = o[j], o[j] = x);
return o;
};
var randorder = shuffle([0,1,2,3,4,5,6]);
var index = 0;
setInterval(function() {
$('.foo:nth-of-type('+(randorder[index++])+')').fadeIn(300);
}, 300);
Solution C:
Keep track of the numbers available in an array. Randomly pick a number. Remove number from said array.
var randnums = [0,1,2,3,4,5,6];
setInterval(function() {
var m = Math.floor(Math.random()*randnums.length);
$('.foo:nth-of-type('+(randnums[m])+')').fadeIn(300);
randnums = randnums.splice(m,1);
}, 300);
You seem to want a non-repeating random number from 0 to 6, so similar to tskuzzy's answer:
var getRand = (function() {
var nums = [0,1,2,3,4,5,6];
var current = [];
function rand(n) {
return (Math.random() * n)|0;
}
return function() {
if (!current.length) current = nums.slice();
return current.splice(rand(current.length), 1);
}
}());
It will return the numbers 0 to 6 in random order. When each has been drawn once, it will start again.
could you try that,
setInterval(function() {
m = Math.floor(Math.random()*7);
$('.foo:nth-of-type(' + m + ')').fadeIn(300);
}, 300);
I like Neal's answer although this is begging for some recursion. Here it is in java, you'll still get the general idea. Note that you'll hit an infinite loop if you pull out more numbers than MAX, I could have fixed that but left it as is for clarity.
edit: saw neal added a while loop so that works great.
public class RandCheck {
private List<Integer> numbers;
private Random rand;
private int MAX = 100;
public RandCheck(){
numbers = new ArrayList<Integer>();
rand = new Random();
}
public int getRandomNum(){
return getRandomNumRecursive(getRand());
}
private int getRandomNumRecursive(int num){
if(numbers.contains(num)){
return getRandomNumRecursive(getRand());
} else {
return num;
}
}
private int getRand(){
return rand.nextInt(MAX);
}
public static void main(String[] args){
RandCheck randCheck = new RandCheck();
for(int i = 0; i < 100; i++){
System.out.println(randCheck.getRandomNum());
}
}
}
Generally my approach is to make an array containing all of the possible values and to:
Pick a random number <= the size of the array
Remove the chosen element from the array
Repeat steps 1-2 until the array is empty
The resulting set of numbers will contain all of your indices without repetition.
Even better, maybe something like this:
var numArray = [0,1,2,3,4,5,6];
numArray.shuffle();
Then just go through the items because shuffle will have randomized them and pop them off one at a time.
Here's a simple fix, if a little rudimentary:
if(nextNum == lastNum){
if (nextNum == 0){nextNum = 7;}
else {nextNum = nextNum-1;}
}
If the next number is the same as the last simply minus 1 unless the number is 0 (zero) and set it to any other number within your set (I chose 7, the highest index).
I used this method within the cycle function because the only stipulation on selecting a number was that is musn't be the same as the last one.
Not the most elegant or technically gifted solution, but it works :)
Use sets. They were introduced to the specification in ES6. A set is a data structure that represents a collection of unique values, so it cannot include any duplicate values. I needed 6 random, non-repeatable numbers ranging from 1-49. I started with creating a longer set with around 30 digits (if the values repeat the set will have less elements), converted the set to array and then sliced it's first 6 elements. Easy peasy. Set.length is by default undefined and it's useless that's why it's easier to convert it to an array if you need specific length.
let randomSet = new Set();
for (let index = 0; index < 30; index++) {
randomSet.add(Math.floor(Math.random() * 49) + 1)
};
let randomSetToArray = Array.from(randomSet).slice(0,6);
console.log(randomSet);
console.log(randomSetToArray);
An easy way to generate a list of different numbers, no matter the size or number:
function randomNumber(max) {
return Math.floor(Math.random() * max + 1);
}
const list = []
while(list.length < 10 ){
let nbr = randomNumber(500)
if(!list.find(el => el === nbr)) list.push(nbr)
}
console.log("list",list)
I would like to add--
var RecordKeeper = {};
SRandom = function () {
currTimeStamp = new Date().getTime();
if (RecordKeeper.hasOwnProperty(currTimeStamp)) {
RecordKeeper[currTimeStamp] = RecordKeeper[currTimeStamp] + 1;
return currTimeStamp.toString() + RecordKeeper[currTimeStamp];
}
else {
RecordKeeper[currTimeStamp] = 1;
return currTimeStamp.toString() + RecordKeeper[currTimeStamp];
}
}
This uses timestamp (every millisecond) to always generate a unique number.
you can do this. Have a public array of keys that you have used and check against them with this function:
function in_array(needle, haystack)
{
for(var key in haystack)
{
if(needle === haystack[key])
{
return true;
}
}
return false;
}
(function from: javascript function inArray)
So what you can do is:
var done = [];
setInterval(function() {
var m = null;
while(m == null || in_array(m, done)){
m = Math.floor(Math.random()*7);
}
done.push(m);
$('.foo:nth-of-type('+m+')').fadeIn(300);
}, 300);
This code will get stuck after getting all seven numbers so you need to make sure it exists after it fins them all.

how to write record names with versions properly in javascript

I need bit help on below issue.
Background:
I have a set of array.
["3a67ef_V1", "3a67ef", "2b678_V1", "1b", "3a67ef_V2", "2b678_V2", "2b678"]
in this array i need to find the curentRecordName andhigher Version numeber
I am creating a file based on record id
For e.g: if record id is 1 then file will be saved as 1a.json
if user want to create another record with same name
i will write as 1a_V1.json
Update: there can be other character as well besides number, but after _V there wont be other letters than numbers
Issue: whenever user is creating same record name file should write as
1a_V1.json
1a_V2.json
1a_V3.json
1a_V4.json
Code goes here
// current record name
var curentRecordName = '2';
//we need check curentRecordName as well as higher version in this array
var recordIDs = ["3a67ef_V1", "3a67ef", "2b678_V1", "1b", "3a67ef_V2", "2b678_V2", "2b678"];
//looping though the array
for (var m = 0; m < recordIDs.length; m++) {
var version = +1;
// if record exist, add record to initial version to 1
// for e.g: if record number 4 is alreday exist then create 4_V1
if (recordIDs[m] === curentRecordName) {
curentRecordName = curentRecordName + '_V' + [version];
break;
}
//if record version 2 exist add version 3, if version 3 exist add version 4 etc
// i need help here please
if (recordIDs[m] === curentRecordName + '_V' + recordIDs[m].split("_V").pop()) {
var adddition = parseInt(recordIDs[m].split("_V").pop()) + 1;
curentRecordName = curentRecordName + '_V' + adddition;
break;
}
}
console.log(curentRecordName);
//Final motive is to create _V3, _V4_, V5 in arrays
Once record name is added, i will save it background
var saveObject = {
"alf_destination": localStorage.getItem('folderNodeRef'),
"prop_cm_name": "report_" + recordName + ".json",
"prop_cm_content": JSON.stringify(this.records),
"prop_mimetype": "text/json"
};
how to do this ?
I just want a logic how to create records by finding high version in array and adding one more bigger version.?
JSFiddle link
any help is appreciated.
You can try using this
// current record name
var curentRecordName = '2';
//we need check curentRecordName as well as higher version in this array
var recordIDs = ["3_V1", "3", "2_V1", "1", "3_V2", "2_V2", "2"];
var possibleIDs = recordIDs.filter((data) => data.split("_")[0] == curentRecordName).sort((first, second) => {
return second.split("_V")[1] - first.split("_V")[1];
});
if (possibleIDs.length > 0) {
var data = possibleIDs[0].split("_V")[0] + "_V" + (Number(possibleIDs[0].split("_V")[0]) + 1);
recordIDs.push(data);
}
console.log(recordIDs);
by finding high version in array and adding one more bigger version
In ES6 you can do that :
https://jsfiddle.net/xjx6koda/
//we need check curentRecordName as well as higher version in this array
var recordIDs = ["3a67ef_V1", "3a67ef", "2b678_V1", "1b", "3a67ef_V2", "2b678_V2", "2b678"];
function getNextRecord(crn) {
const [highestVersion] = recordIDs
.filter(r => r.indexOf(`${crn}_V`) === 0 || crn === r)
.map(r => (crn === r) ? 0 : parseFloat(r.replace(`${crn}_V`,'')) )
.sort((a,b) => a < b)
return highestVersion >= 0 ? `${crn}_V${highestVersion + 1}` : crn;
}
console.log('with 3a67ef : ', getNextRecord('3a67ef'))
// with 3a67ef : 3a67ef_V3
console.log('with new : ', getNextRecord('new'))
// with new : new
console.log('with 1b : ', getNextRecord('1b'))
// with 1b : 1b_V1

JavaScript: Subtracting ranges of numbers

I'm trying to write a JS function which has two parameters, include and exclude, each an array of objects {X, Y} which represents a range of numbers from X to Y, both included.
The output is the subtraction of all the ranges in include with all the ranges in exclude.
For example:
include = [ {1,7}, {9,10}, {12,14} ]
exclude = [ {4,5}, {11,20} ]
output = [ {1,3}, {6,7}, {9,10} ]
{4,5} broke {1,7} into two range objects: {1,3} and {6,7}
{9,10} was not affected
{12,14} was removed entirely
You can use sweep line algorithm. For every number save what it represents (start and end, inclusion and exclusion ). Then put all the number in an array and sort it. Then iteratively remove elements from the array and perform the appropriate operation.
include_list = [[1,7]]
exclude_list = [[4,5]]
(1,start,inclusion),(4,start,exclusion),(5,end,exclusion),(7,end,inclusion)
include = 0
exclude = 0
cur_element = (1,start,inclusion) -> include = 1, has_open_range = 1, range_start = 1 // we start a new range starting at 1
cur_element = (4,start,exclusion) -> exclude = 1, has_open_range = 0, result.append ( [1,4] ) // we close the open range and add range to result
cur_element = (5,end,exclusion) -> exclude = 0, has_open_range = 1, range_start = 5 // because include was 1 and exclude become 0 we must create a new range starting at 5
cur_element = (7,end,inclusion) -> include = 0, has_open_range = 0, result.append([5,7]) // include became zero so we must close the current open range so we add [5,7] to result
maintain variables include and exclude increment them with start of the respective elements and decrement them upon receiving end elements. According to the value of include and exclude you can determine wether you should start a new range, close the open range, or do nothing at all.
This algorithm runs in linear time O(n).
The rule for integer set arithmetic for subtraction of two sets X,Y is
X − Y := {x − y | x ∈ X, y ∈ Y }
but that's not what you want, as it seems.
You can assume ordered sets in your example which allows you to set every occurrence of x==y as an arbitrary value in a JavaScript array and use that to split there. But you don't need that.
The set difference {1...7}\{4...5} gets expanded to {1,2,3,4,5,6,7}\{4,5}. As you can easily see, a subtraction with the rule of set arithmetic would leave {1,2,3,0,0,6,7} and with normal set subtraction (symbol \) you get {1,2,3,6,7}.
The set difference {12...14}\{11...20} gets expanded to {12,13,14}\{11,12,13,14,15,16,17,18,19,20}; the set arithm. difference is {-11,0,0,0,-15,-16,...,-20} but the normal set-subtraction leaves the empty set {}.
Handling operations with the empty set is equivalent to normal arithmetic {x}-{}={x} and {}-{x} = {-x} for arithmetic set rules and {x}\{}={x},{}\{x}= {} with normal rules
So what you have to use here, according to your example, are the normal set rules. There is no need to expand the sets, they can be assumed to be dense.
You can use relative differences(you may call them distances).
With {1...7}\{4...5} the first start is small then the second start and the first end is greater the the second end, which resulted in two different sets.
With {12...14}\{11...20} the first start is greater than the second start and the first end is lower then the second end which resulted in an empty set.
The third example makes use of the empty-set rule.
Do you need an example snippet?
Here's an answer that works with fractions and that isnt just brute forcing. I've added comments to explain how it works. It may seem big the the premise is simple:
create a method p1_excluding_p2 that accepts points p1 and p2 and returns of an array of points that exist after doing p1 - p2
create a method points_excluding_p2 which performs the EXACT same operation as above, but this time allow us to pass an array of points, and return an array of points that exist after subtracting p2 from all the points in our array, so now we have (points) - p2
create a method p1_excluding_all which takes the opposite input as above. This time, accept one point p1 and many exclusion points, and return the array of points remaining after subtracting all the exclusion points. This is actually very easy to create now. We simply start off with [p1] and the first exclusion point (exclusion1) and feed this into points_excluding_p2. We take the array that comes back (which will be p1 - exclusion1) and feed this into points_excluding_p2 only this time with exclusion2. We continue this process until we've excluded every exclusion point, and we're left with an array of p1 - (all exclusion points)
now that we have the power to perform p1 - (all exclusion points), its just a matter of looping over all our points and calling p1_excluding_all, and we're left with an array of every point subtract every exclusion point. We run our results through remove_duplicates incase we have any duplicate entries, and that's about it.
The code:
var include = [ [1,7], [9,10], [12,14] ]
var exclude = [ [4,5], [11,20] ]
/* This method is just a small helper method that takes an array
* and returns a new array with duplicates removed
*/
function remove_duplicates(arr) {
var lookup = {};
var results = [];
for(var i = 0; i < arr.length; i++) {
var el = arr[i];
var key = el.toString();
if(lookup[key]) continue;
lookup[key] = 1;
results.push(el);
}
return results;
}
/* This method takes 2 points p1 and p2 and returns an array of
* points with the range of p2 removed, i.e. p1 = [1,7]
* p2 = [4,5] returned = [[1,3],[6,7]]
*/
function p1_excluding_p2(p1, p2) {
if(p1[1] < p2[0]) return [p1]; // line p1 finishes before the exclusion line p2
if(p1[0] > p2[1]) return [p1]; // line p1 starts after exclusion line p1
var lines = [];
// calculate p1 before p2 starts
var line1 = [ p1[0], Math.min(p1[1], p2[0]-1) ];
if(line1[0] < line1[1]) lines.push(line1);
// calculate p1 after p2 ends
var line2 = [ p2[1]+1, p1[1] ];
if(line2[0] < line2[1]) lines.push(line2);
// these contain the lines we calculated above
return lines;
}
/* this performs the exact same operation as above, only it allows you to pass
* multiple points (but still just 1 exclusion point) and returns results
* in an identical format as above, i.e. points = [[1,7],[0,1]]
* p2 = [4,5] returned = [[0,1],[1,3],[6,7]]
*/
function points_excluding_p2(points, p2) {
var results = [];
for(var i = 0; i < points.length; i++) {
var lines = p1_excluding_p2(points[i], p2);
results.push.apply(results, lines); // append the array lines to the array results
}
return results;
}
/* this method performs the same operation only this time it takes one point
* and multiple exclusion points and returns an array of the results.
* this is the important method of: given 1 point and many
* exclusion points, return the remaining new ranges
*/
function p1_excluding_all(p1, excluded_pts) {
var checking = [p1];
var points_leftover = [];
for(var i = 0; i < exclude.length; i++) {
checking = points_excluding_p2(checking, exclude[i]);
}
return remove_duplicates(checking);
}
/* now that we have a method that we can feed a point and an array of exclusion
* points, its just a simple matter of throwing all our points into this
* method, then at the end remove duplicate results for good measure
*/
var results = [];
for(var i = 0; i < include.length; i++) {
var lines = p1_excluding_all(include[i], exclude);
results.push.apply(results, lines); // append the array lines to the array results
}
results = remove_duplicates(results);
console.log(results);
which returns:
[[1,3],[6,7],[9,10]]
NOTE: include = [ {1,7}, {9,10}, {12,14} ] is not valid javascript, so I assumed you as passing in arrays of arrays instead such as:
include = [ [1,7], [9,10], [12,14] ]
Brute force method (a solution, may not be the most eloquent):
function solve_range(include, exclude) {
numbers = [];
include.forEach(function (range) {
for (i = range[0]; i <= range[1]; i++) {
numbers[i] = true;
}
});
exclude.forEach(function (range) {
for (i = range[0]; i <= range[1]; i++) {
numbers[i] = false;
}
});
contiguous_start = null;
results = [];
for (i = 0; i < numbers.length; i++) {
if (numbers[i] === true) {
if (contiguous_start == null) {
contiguous_start = i;
}
} else {
if (contiguous_start !== null) {
results[results.length] = [contiguous_start, i - 1];
}
contiguous_start = null;
}
}
return results;
}
var include = [
[1, 7],
[9, 10],
[12, 14]
];
var exclude = [
[4, 5],
[11, 20]
];
var output = solve_range(include, exclude);
https://jsfiddle.net/dwyk631d/2/
Here's a working solution that handles the 4 possible overlap scenarios for an exclusion range.
var include = [{from:1, to: 7},{from: 9, to: 10},{from: 12, to: 14}];
var exclude = [{from:4, to: 5}, {from: 11, to: 20}];
//result: {1,3}, {6,7}, {9,10}
var resultList = [];
for (var i=0;i<include.length;i++){
var inc = include[i];
var overlap = false;
for (var x=0;x<exclude.length;x++ ){
var exc = exclude[x];
//4 scenarios to handle
if (exc.from >= inc.from && exc.to <= inc.to){
//include swallows exclude - break in two
resultList.push({from: inc.from, to: exc.from - 1});
resultList.push({from: exc.to + 1, to: inc.to});
overlap = true;
}else if (exc.from <= inc.from && exc.to >= inc.to){
//exclude swallows include - exclude entire range
overlap = true;
break;
}else if (exc.from <= inc.from && exc.to <= inc.to && exc.to >= inc.from){
//exclusion overlaps on left
resultList.push({from: exc.to, to: inc.to});
overlap = true;
}else if (exc.from >= inc.from && exc.to >= inc.to && exc.from <= inc.to){
//exclusion overlaps on right
resultList.push({from: inc.from, to: exc.from - 1});
overlap = true;
}
}
if (!overlap){
//no exclusion ranges touch the inclusion range
resultList.push(inc);
}
}
console.log(resultList);
Perhaps we can make it slightly more efficient by merging labeled intervals into one sorted list:
include = [ {1,7}, {9,10}, {12,14} ]
exclude = [ {4,5}, {11,20} ]
merged = [ [1,7,0], [4,5,1], [9,10,0], [11,20,1], [12,14,0] ];
Then, traverse the list and for any excluded interval, update any surrounding affected intervals.
try this
function excludeRange(data, exclude) {
data = [...data] // i don't want inplace edit
exclude.forEach(e=>{
data.forEach((d,di)=>{
// check intersect
if (d[0] <= e[1] && e[0] <= d[1]) {
// split into two range: [Ax, Bx-1] and [By+1, Ay]
var ranges = [
[d[0], e[0]-1],
[e[1]+1, d[1]],
]
// keep only valid range where x <= y
ranges = ranges.filter(e=>e[0]<=e[1])
// replace existing range with new ranges
data.splice(di, 1, ...ranges)
}
})
})
return data
}
I try to implement this short and simple as possible
edit: add explain and update more readable code
the algorithm with A-B
if intersect -> we split into two range: [Ax, Bx-1] and [By+1, Ay]
then we filter out invalid range (where x > y)
else: keep A

Small Straight (Yahtzee) Algorithm

I have created a working javascript function to check an array of 5 numbers for a small straight, in a Yahtzee game I'm making. I've tested it to no end and I'm confident it works 100% of the time, but it is also probably the worst algorithm of all time in terms of being efficient. Here is what it looks like:
function calcSmstraight() {
var sum = 0;
var r = new Array();
var r2 = new Array();
var counter = 0;
var temp;
var bool = false;
var bool2 = false;
r[0] = document.getElementById('setKeep1').value;
r[1] = document.getElementById('setKeep2').value;
r[2] = document.getElementById('setKeep3').value;
r[3] = document.getElementById('setKeep4').value;
r[4] = document.getElementById('setKeep5').value;
// Move non-duplicates to new array
r2[0] = r[0];
for(var i=0; i<r.length; i++) {
for(var j=0; j<r2.length; j++) {
if(r[i] == r2[j]) {
bool2 = true; // Already in new list
}
}
// Add to new list if not already in it
if(!bool2) {
r2.push(r[i]);
}
bool2 = false;
}
// Make sure list has at least 4 different numbers
if(r2.length >= 4) {
// Sort dice from least to greatest
while(counter < r2.length) {
if(r2[counter] > r2[counter+1]) {
temp = r2[counter];
r2[counter] = r2[counter+1];
r2[counter+1] = temp;
counter = 0;
} else {
counter++;
}
}
// Check if the dice are in order
if(((r2[0] == (r2[1]-1)) && (r2[1] == (r2[2]-1)) && (r2[2] == (r2[3]-1)))
|| ((r2[1] == (r2[2]-1)) && (r2[2] == (r2[3]-1)) && (r2[3] == (r2[4]-1)))) {
bool = true;
}
}
if(bool) {
// If small straight give 30 points
sum = 30;
}
return sum;
}
My strategy is to:
1) Remove duplicates by adding numbers to a new array as they occur
2) Make sure the new array is at least 4 in length (4 different numbers)
3) Sort the array from least to greatest
4) Check if the first 4 OR last 4 (if 5 in length) numbers are in order
My question:
Does anyone know a way that I can improve this method? It seems ridiculously terrible to me but I can't think of a better way to do this and it at least works.
Given that you're implementing a Yahtzee game you presumably need to test for other patterns beyond just small straights, so it would be better to create the array of values before calling the function so that you can use them in all tests, rather than getting the values from the DOM elements inside the small straight test.
Anyway, here's the first way that came to my mind to test for a small straight within an array representing the values of five six-sided dice:
// assume r is an array with the values from the dice
r.sort();
if (/1234|2345|3456/.test(r.join("").replace(/(.)\1/,"$1") {
// is a small straight
}
Note that you can sort an array of numbers using this code:
r2.sort(function(a,b){return a-b;});
...but in your case the values in the array are strings because they came from the .value attribute of DOM elements, so a default string sort will work with r2.sort(). Either way you don't need your own sort routine, because JavaScript provides one.
EDIT: If you assume that you can just put the five values as a string as above you can implement tests for all possible combinations as a big if/else like this:
r.sort();
r = r.join("");
if (/(.)\1{4}/.test(r)) {
alert("Five of a Kind");
} else if (/(.)\1{3}/.test(r)) {
alert("Four of a Kind");
} else if (/(.)\1{2}(.)\2|(.)\3(.)\4{2}/.test(r)) {
alert("Full House");
} else if (/(.)\1{2}/.test(r)) {
alert("Three of a Kind");
} else if (/1234|2345|3456/.test( r.replace(/(.)\1/,"$1") ) {
alert("Small Straight");
} // etc.
Demo: http://jsfiddle.net/4Qzfw/
Why don't you just have a six-element array of booleans indicating whether a number is present, then check 1-4, 2-5, and 3-6 for being all true? In pseudocode:
numFlags = array(6);
foreach(dice)
numFlags[die.value-1] = true;
if(numFlags[0] && numFlags[1] && numFlags[2] && numFlags[3]) return true
//Repeat for 1-4 and 2-5
return false
This wouldn't be a useful algorithm if you were using million-sided dice, but for six-siders there are only three possible small straights to check for, so it's simple and straightforward.
I do not play Yahtzee, but I do play cards, and it would appear the algorithm might be similar. This routine, written in ActionScript (my JavaScript is a bit rusty) has been compiled but not tested. It should accept 5 cards for input, and return a message for either straights greater than 3 cards or pairs or higher.
private function checkCards(card1:int,card2:int,card3:int,card4:int,card5:int):String
{
// Assumes that the 5 cards have a value between 0-12 (Ace-King)
//The key to the routine is using the card values as pointers into an array of possible card values.
var aryCardValues:Array = new Array(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
aryCardValues[card1] += 1;
aryCardValues[card1] += 1;
aryCardValues[card1] += 1;
aryCardValues[card1] += 1;
aryCardValues[card1] += 1;
var aryCardNames:Array = new Array("Ace", "2", "3", "4", "5", "6", "7", "8", "9", "10", "Jack", "Queen", "King");
var strOutMessage:String;
var intCardCount:int = 0;
var strSeperator:String;
var strHighCard:String;
for (var i:int = 0;i < aryCardValues.length;i++)
{
//Check for runs of three of a kind or greater.
if (aryCardValues[i] >= 2)
{
strOutMessage = strOutMessage + strSeperator + i + "-" + aryCardNames[i] + "s";
strSeperator = " & ";
}
//Check for values in a straight.
if (aryCardValues[i] > 0)
{
intCardCount++;
if (intCardCount > 3)strHighCard = aryCardNames[i];
}
else
{
if (intCardCount < 3)intCardCount = 0;
}
}
if (intCardCount > 3) strOutMessage = intCardCount + " run " + strHighCard + " High."
return strOutMessage;
}
It may not be as concise as the regular expressions used above, but it might be more readable and easily modified. One change that could be made is to pass in an array of cards rather than discrete variables for each card.

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