Develop Reference

Find the largest sequence of five numbers in a string in Javascript

HI everyone hopefully an easy one. I have split a string example below in to 5 digit blocks I now need to find the largest 5 number sequence, and not sure how to do this any help much appreciated. "731671765313306249192251196744265747423553491949349698352036854250632623957831801698480186947885184385861560789112949495459501737958331952853208805511125406987471585238630507156932909632952274430435576689664895
function solution(digits){
let output = digits.match(/.{1,5}/g);
console.log(output);
}

This approach (of splitting into chunks of 5), will not always give the optimal result, as you are not looking at every possible chunk of 5... only those that start at an index that is a multiple of 5.
So just iterate through every array index, and then take 5 characters from there, and compare...
let str = "731671765313306249192251196744265747423553491949349698352036854250632623957831801698480186947885184385861560789112949495459501737958331952853208805511125406987471585238630507156932909632952274430435576689664895";
let best = "";
for (let i = 5; i <= str.length; i++) {
let slice = str.slice(i - 5, i);
if (slice > best) best = slice;
}
console.log(best);

Emojis to/from codepoints in Javascript

In a hybrid Android/Cordova game that I am creating I let users provide an identifier in the form of an Emoji + an alphanumeric - i.e. 0..9,A..Z,a..z - name. For example
🙋‍️Stackoverflow
Server-side the user identifiers are stored with the Emoji and Name parts separated with only the Name part requiried to be unique. From time-to-time the game displays a "league table" so the user can see how well they are performing compared to other players. For this purpose the server sends back a sequence of ten "high score" values consisting of Emoji, Name and Score.
This is then presented to the user in a table with three columns - one each for Emoji, Name and Score. And this is where I have hit a slight problem. Initially I had quite naively assumed that I could figure out the Emoji by simply looking at handle.codePointAt(0). When it dawned on me that an Emoji could in fact be a sequence of one or more 16 bit Unicode values I changed my code as follows
Part 1:Dissecting the user supplied "handle"
var i,username,
codepoints = [],
handle = "🙋‍️StackOverflow",
len = handle,length;
while ((i < len) && (255 < handle.codePointAt(i)))
{codepoints.push(handle.codePointAt(i));i += 2;}
username = handle.substring(codepoints.length + 1);
At this point I have the "disssected" handle with
codepoints =  [128587, 8205, 65039];
username = 'Stackoverflow;
A note of explanation for the i += 2 and the use of handle.length above. This article suggests that
handle.codePointAt(n) will return the code point for the full surrogate pair if you hit the leading surrogate. In my case since the Emoji has to be first character the leading surrogates for the sequence of 16 bit Unicodes for the emoji are at 0,2,4....
From the same article I learnt that String.length in Javascript will return the number of 16 bit code units.
Part II - Re generating the Emojis for the "league table"
Suppose the league table data squirted back to the app by my servers has the entry {emoji: [128583, 8205, 65039],username:"Stackexchange",points:100} for the emoji character 🙇‍️. Now here is the bothersome thing. If I do
var origCP = [],
i = 0,
origEmoji = '🙇‍️',
origLen = origEmoji.length;
while ((i < origLen) && (255 < origEmoji.codePointAt(i))
{origCP.push(origEmoji.codePointAt(i);i += 2;}
I get
origLen = 5, origCP = [128583, 8205, 65039]
However, if I regenerate the emoji from the provided data
var reEmoji = String.fromCodePoint.apply(String,[128583, 8205, 65039]),
reEmojiLen = reEmoji.length;
I get
reEmoji = '🙇‍️'
reEmojiLen = 4;
So while reEmoji has the correct emoji its reported length has mysteriously shrunk down to 4 code units in place of the original 5.
If I then extract code points from the regenerated emoji
var reCP = [],
i = 0;
while ((i < reEmojiLen) && (255 < reEmoji.codePointAt(i))
{reCP.push(reEmoji.codePointAt(i);i += 2;}
which gives me
reCP = [128583, 8205];
Even curioser, origEmoji.codePointAt(3) gives the trailing surrogate pair value of 9794 while reEmoji.codePointAt(3) gives the value of the next full surrogate pair 65039.
I could at this point just say
Do I really care?
After all, I just want to show the league table emojis in a separate column so as long as I am getting the right emoji the niceties of what is happening under the hood do not matter. However, this might well be stocking up problems for the future.
Can anyone here shed any light on what is happening?

emojis are more complicated than just single chars, they come in "sequences", e.g. a zwj-sequence (combine multiple emojis into one image) or a presentation sequence (provide different variations of the same symbol) and some more, see tr51 for all the nasty details.
If you "dump" your string like this
str = "🙋‍️StackOverflow"
console.log(...[...str].map(x => x.codePointAt(0).toString(16)))
you'll see that it's actually an (incorrectly formed) zwj-sequence wrapped in a presentation sequence.
So, to slice emojis accurately, you need to iterate the string as an array of codepoints (not units!) and extract plane 1 CPs (>0xffff) + ZWJ's + variation selectors. Example:
function sliceEmoji(str) {
let res = ['', ''];
for (let c of str) {
let n = c.codePointAt(0);
let isEmoji = n > 0xfff || n === 0x200d || (0xfe00 <= n && n <= 0xfeff);
res[1 - isEmoji] += c;
}
return res;
}
function hex(str) {
return [...str].map(x => x.codePointAt(0).toString(16))
}
myStr = "🙋‍️StackOverflow"
console.log(sliceEmoji(myStr))
console.log(sliceEmoji(myStr).map(hex))

how to generate unique ID character using letters a-z

Here is a little challenge, I hope it will be useful for others too.
Task is to obtain an ID character from alphabets of english language. a-to-z
My solution currently allows ID (words) of 26 diff length (max possible). with 90 possible words.
I know this can be increased if we pick random characters after single character IDs are obtained (done with.) (But) I am finding it hard to figure out how to manage NOT hitting a combination already found (ID has to be unique). As we see it takes a long time if it starts finding the same combinations over and over. this probability increases as we obtain more and more ID-combinations.
Here is my code and fiddle to test and check:
fiddle
code:
html
<p>
start
</p>
jquery:
function addto(t) {
$("p").append("<b>" + t + "</b>");
}
global_ID_array = [];
lowerAlpha = "abcdefghijklmnopqrstuvwxyz";
var myIDlength = 1;
function getIDChar (){
do {
var myIDchar = lowerAlpha.substr(0, myIDlength);
lowerAlpha = lowerAlpha.replace(myIDchar,'');
if (lowerAlpha.length < myIDlength){
lowerAlpha = "abcdefghijklmnopqrstuvwxyz"; //reset
myIDlength++;
}
} while (global_ID_array.indexOf(myIDchar) > -1)
global_ID_array.push(myIDchar);
addto(myIDlength+':'+global_ID_array.length+',');
}
do{
getIDChar();
}while (myIDlength < 26);
addto('<br \>myIDlength='+myIDlength);
addto('<br \>global_ID_array last val='+global_ID_array[global_ID_array.length-1]+'<p>');

To get started, instead of thinking about the IDs in terms of letters, think about it in terms of numbers.
Since there are 26 possible characters, each character can be considered as a digit of a base-26 numeric system, with a == 0, and z == 25. The problem now boils down to generating a number and converting it to base-26 using the alphabets as digits. Since the ID length is 26 characters, we can generate up to 26^26 unique IDs.
Now, to make sure that the ID generated is unique (up to 26^26 generated IDs), we need to find a way to generate a unique number every time. The simplest way to do this is to initialize a counter at 0 and use it to generate the ID. Every time an ID is done generating, increment the counter. Of course, this is a very deterministic generation algorithm, but you could use a seeded random number generator that guarantees the uniqueness of random numbers generated in a range.
The algorithm may look as follows:
n = random(0, 26^26 - 1)
id = "a" * 26
// chars[i] is the character representing the base-26 digit i;
// you may change/shuffle the list as you please
chars = ['a', 'b', 'c', ..., 'y', 'z']
for i in 0..26 {
// Get the character corresponding to the next base-26 digit of n (n % 26)
id[26 - i] = chars[n % 26]
n /= 26
}

How to count occurrence of multiple sub-string in a long string with JavaScript

I am a fresh with JavaScript. I just tried a lot, but did not get the answer and information to show how to count occurrence of multiple sub-string in a long string at one time.
Further information: I need get the occurrence of these sub-string and if the number of their occurrence to much, I need replace them at one time,so I need get the occurrence at one time.
Here is an example:
The long string Text as below,
Super Bowl 50 was an American football game to determine the champion of the National Football League (NFL) for the 2015 season. The American Football Conference (AFC) champion Denver Broncos defeated the National Football Conference (NFC) champion Carolina Panthers 24–10 to earn their third Super Bowl title. The game was played on February 7, 2016, at Levi's Stadium in the San Francisco Bay Area at Santa Clara, California. As this was the 50th Super Bowl, the league emphasized the "golden anniversary" with various gold-themed initiatives, as well as temporarily suspending the tradition of naming each Super Bowl game with Roman numerals (under which the game would have been known as "Super Bowl L"), so that the logo could prominently feature the Arabic numerals 50.
The sub-string is a question, but what I need is to count each word occurrence in this sub-string at one time. for example, the word "name","NFL","championship","game" and "is","the" in this string.
What is the name of NFL championship game?
One of problems is some sub-string is not in the text, and some have shown many times.(which I might replaced it)
The Code I have tried as below, it is wrong, I have tried many different ways but no good results.
$(".showMoreFeatures").click(function(){
var text= $(".article p").text(); // This is to get the text.
var textCount = new Array();
// Because I use match, so for the first word "what", will return null, so
this is to avoid this null. and I was plan to get the count number, if it is
more than 7 or even more, I will replace them.
var qus = item2.question; //This is to get the sub-string
var checkQus = qus.split(" "); // I split the question to words
var newCheckQus = new Array();
// This is the array I was plan put the sub-string which count number less than 7, which I really needed words.
var count = new Array();
// Because it is a question as sub-string and have many words, so I wan plan to get their number and put them in a array.
for(var k =0; k < checkQus.length; k++){
textCount = text.match(checkQus[k],"g")
if(textCount == null){
continue;
}
for(var j =0; j<checkQus.length;j++){
count[j] = textCount.length;
}
//count++;
}
I was tried many different ways, and searched a lot, but no good results. The above code just want to show what I have tried and my thinking(might totally wrong). But actually it is not working , if you know how to implement it,solve my problem, please just tell me, no need to correct my code.
Thanks very much.

If I have understood the question correctly then it seems you need to count the number of times the words in the question (que) appear in the text (txt)...
var txt = "Super Bowl 50 was an American ...etc... Arabic numerals 50.";
var que = "What is the name of NFL championship game?";
I'll go through this in vanilla JavaScript and you can transpose it for JQuery as required.
First of all, to focus on the text we can make things a little simpler by changing the strings to lowercase and removing some of the punctuation.
// both strings to lowercase
txt = txt.toLowerCase();
que = que.toLowerCase();
// remove punctuation
// using double \\ for proper regular expression syntax
var puncArray = ["\\,", "\\.", "\\(", "\\)", "\\!", "\\?"];
puncArray.forEach(function(P) {
// create a regular expresion from each punctuation 'P'
var rEx = new RegExp( P, "g");
// replace every 'P' with empty string (nothing)
txt = txt.replace(rEx, '');
que = que.replace(rEx, '');
});
Now we can create a cleaner array from str and que as well as a hash table from que like so...
// Arrays: split at every space
var txtArray = txt.split(" ");
var queArray = que.split(" ");
// Object, for storing 'que' counts
var queObject = {};
queArray.forEach(function(S) {
// create 'queObject' keys from 'queArray'
// and set value to zero (0)
queObject[S] = 0;
});
queObject will be used to hold the words counted. If you were to console.debug(queObject) at this point it would look something like this...
console.debug(queObject);
/* =>
queObject = {
what: 0,
is: 0,
the: 0,
name: 0,
of: 0,
nfl: 0,
championship: 0,
game: 0
}
*/
Now we want to test each element in txtArray to see if it contains any of the elements in queArray. If the test is true we'll add +1 to the equivalent queObject property, like this...
// go through each element in 'queArray'
queArray.forEach(function(A) {
// create regular expression for testing
var rEx = new RegExp( A );
// test 'rEx' against elements in 'txtArray'
txtArray.forEach(function(B) {
// is 'A' in 'B'?
if (rEx.test(B)) {
// increase 'queObject' property 'A' by 1.
queObject[A]++;
}
});
});
We use RegExp test method here rather than String match method because we just want to know if "is A in B == true". If it is true then we increase the corresponding queObject property by 1. This method will also find words inside words, such as 'is' in 'San Francisco' etc.
All being well, logging queObject to the console will show you how many times each word in the question appeared in the text.
console.debug(queObject);
/* =>
queObject = {
what: 0
is: 2
the: 17
name: 0
of: 2
nfl: 1
championship: 0
game: 4
}
*/
Hoped that helped. :)
See MDN for more information on:
Array.forEach()
Object.keys()
RegExp.test()

Adding space to fill array length

I am working with a javascript program that needs to be formatted a certain way. Basically, I need to have each section of information from an array be a set length, for example 12 characters long, and no more than that.
The problem I am running into comes when a value in the array is NOT 12 characters long. If I have a value that is less than the 12 characters the remaining character allotment needs to be filled with blank spaces.
The length of each section of information varies in size and is not always 12. How can I add X number of blank spaces, should the length not meet the maximum requirement, for each section?
This is where I am at with adding space:
str = str + new Array(str.length).join(' ');
I am pretty sure what I have above is wrong but I believe I am on the right track with the .join function. Any ideas?
EDIT: I was asked to show a wanted outcome. It is a bit complicated because this javascript is being run out of a web report tool and not out of something like Visual Studio so its not traditional JS.
The outcome expected should look something like:
Sample Image
So as shown above the data is in one line, cutting off longer strings of information or filling in blank spaces if its too short for the "column" to keep that nice even look.

try this code and leverage the wonders of the map function:
let say your array is:
var myArr = ["123456789012", "12345678901", "123"];
now just apply this function
myArr.map(function(item){ //evalueate each item inside the array
var strLength = item.length; //apply this function to each item
if (strLength < 12){
return item + ' '.repeat(12-item.length) //add the extra spaces as needed
} else {
return item; // return the item because it's length is 12 or +
}
})
What you are looking for is the ' '.repeat(x) - where x is the times you want to repeat the string you have set, it could be '*'.repeat(2) and you would get '**', if you want to understand more about it look at the docs

depending on which version of javascript, this might work:
if (str.length < 12) str += ' '.repeat(12 - str.length);

Not exactly sure how you're setup -- but something like the following will accept an array and return another array with all its values being 12 characters in length.
var array = ['Test', 'Testing', 'Tested', 'This is not a Test'];
var adjustedArray = correctLength(array, 12);
function correctLength(array, length) {
array.map(function(v, i) {
if (array[i].length < length) {
array[i] += Array((length+1) - array[i].length).join('_');
}
// might not need this if values are already no greater than 12
array[i] = array[i].substring(0, length);
});
return array;
}
console.log(adjustedArray);