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Identifying the identical elements in two arrays with same location(index)

Ok, so I want to return the elements that are present in both provided arrays having the same index location.
exe1 = [A,B,C,D,N]
exe2 = [B,D,C,A,T]
it should return only C
I've tried looping them by nested loops but doesn't work, here is what I've tried:
let testing = []
for (let i = 0; i < exe1.length; i++){
for(let j = 0; j < exe2.length; j++){
if(exe1[i] === exe2[j]){
testing.push(exe1[i])
}
}
};
return testing;
mind the names of the arrays, please

You can use a simple filter to only include values in exe1 that have the same value at the same index of exe2.
const exe1 = ['A','B','C','D','N'];
const exe2 = ['B','D','C','A','T'];
const testing = exe1.filter((val, i) => val === exe2[i]);
console.log(testing)

If you want to create a function that can do this and the datatypes are primitives you can do something like this. Just a loop that goes through each index, checks both arrays, and returns the value that is the same.
const exe1 = ["A","B","C","D","N"];
const exe2 = ["B","D","C","A","T"];
function getElementsThatAreTheSame(arr1, arr2) {
const minLength = Math.min(arr1.length, arr2.length);
const sameArray = [];
for (let i = 0; i < minLength; i++) {
const item1 = arr1[i];
const item2 = arr2[i];
if (item1 == item2) sameArray.push(item1);
}
return sameArray;
}
const sameItems = getElementsThatAreTheSame(exe1, exe2);
console.log(sameItems)
However you could also use the filter method to accomplish this pretty easily as follows:
const exe1 = ["A","B","C","D","N"];
const exe2 = ["B","D","C","A","T"];
const sameArr = exe1.filter((e, i) => exe2[i] == e);
console.log(sameArr);
the filter method will take a function as an argument to which is passed the element in the array and the index of that element. We can just check the second array at that index and make sure it is the same element.
Both these approaches will not verify if it is two objects which have the same content, but are different objects. i.e. {foo: "bar"} !== {foo: "bar"}

I have a array of string have to find all the common character present from all strings

I have a array of string.
let arr=["robin","rohit","roy"];
Need to find all the common character present in all the strings in array.
Output Eg: r,o
I have tried to create a function for above case with multiple loops but i want to know what should be the efficient way to achive it.

Here's a functional solution which will work with an array of any iterable value (not just strings), and uses object identity comparison for value equality:
function findCommon (iterA, iterB) {
const common = new Set();
const uniqueB = new Set(iterB);
for (const value of iterA) if (uniqueB.has(value)) common.add(value);
return common;
}
function findAllCommon (arrayOfIter) {
if (arrayOfIter.length === 0) return [];
let common = new Set(arrayOfIter[0]);
for (let i = 1; i < arrayOfIter.length; i += 1) {
common = findCommon(common, arrayOfIter[i]);
}
return [...common];
}
const arr = ['robin', 'rohit', 'roy'];
const result = findAllCommon(arr);
console.log(result);

const arr = ["roooooobin","rohit","roy"];
const commonChars = (arr) => {
const charsCount = arr.reduce((sum, word) => {
const wordChars = word.split('').reduce((ws, c) => {
ws[c] = 1;
return ws;
}, {});
Object.keys(wordChars).forEach((c) => {
sum[c] = (sum[c] || 0) + 1;
});
return sum;
}, {});
return Object.keys(charsCount).filter(key => charsCount[key] === arr.length);
}
console.log(commonChars(arr));

Okay, the idea is to count the amount of times each letter occurs but only counting 1 letter per string
let arr=["robin","rohit","roy"];
function commonLetter(array){
var count={} //object used for counting letters total
for(let i=0;i<array.length;i++){
//looping through the array
const cache={} //same letters only counted once here
for(let j=0;j<array[i].length;j++){
//looping through the string
let letter=array[i][j]
if(cache[letter]!==true){
//if letter not yet counted in this string
cache[letter]=true //well now it is counted in this string
count[letter]=(count[letter]||0)+1
//I don't say count[letter]++ because count[letter] may not be defined yet, hence (count[letter]||0)
}
}
}
return Object.keys(count)
.filter(letter=>count[letter]===array.length)
.join(',')
}
//usage
console.log(commonLetter(arr))

No matter which way you choose, you will still need to count all characters, you cannot get around O(n*2) as far as I know.
arr=["robin","rohit","roy"];
let commonChars = sumCommonCharacters(arr);
function sumCommonCharacters(arr) {
data = {};
for(let i = 0; i < arr.length; i++) {
for(let char in arr[i]) {
let key = arr[i][char];
data[key] = (data[key] != null) ? data[key]+1 : 1;
}
}
return data;
}
console.log(commonChars);

Here is a 1 liner if anyone interested
new Set(arr.map(d => [...d]).flat(Infinity).reduce((ac,d) => {(new RegExp(`(?:.*${d}.*){${arr.length}}`)).test(arr) && ac.push(d); return ac},[])) //{r,o}

You can use an object to check for the occurrences of each character. loop on the words in the array, then loop on the chars of each word.
let arr = ["robin","rohit","roy"];
const restWords = arr.slice(1);
const result = arr[0].split('').filter(char =>
restWords.every(word => word.includes(char)))
const uniqueChars = Array.from(new Set(result));
console.log(uniqueChars);

Parsing JavaScript string into 2 arrays

You have a string that is in a following format: "Applejack=A.J.+Applecar,Lemon+Vodka=AlfieCocktail+ Sunset + SexOnTheBeach" and etc.
In Javascript (use .split()), write code to parse a string like this(can be 100000 characters long) that puts the input in 2 different arrays(array key, array values) such that the arrays would llok like the following:
key = ["Applejack", "Lemon+Vodka"]
values = ["A.J+Applecar","AlfieCocktail+Sunset+SexOnTheBeach"]

key = string.split(',').map(x=>x.split("=")[0])
values = string.split(',').map(x=>x.split("=")[1])

You could do something like this
var str = "Applejack=A.J.+Applecar,Lemon+Vodka=AlfieCocktail+ Sunset + SexOnTheBeach";
var first = str.split(',');
var keys = [];
var values = [];
for(let i = 0; i < first.length; i++){
let in_two = first[i].split('=');
keys.push(in_two[0]);
values.push(in_two[1]);
}
console.log(keys);
console.log(values);

You can do it like this:
let str = "Applejack=A.J.+Applecar,Lemon+Vodka=AlfieCocktail+ Sunset + SexOnTheBeach";
let allValues = str.split(','), keys = [], values = [];
allValues.forEach(value => {
const [k,v] = value.split('=');
keys.push(k);
values.push(v);
})
console.log(keys,values);

You can simply use map with reduce.
const str =
"Applejack=A.J.+Applecar,Lemon+Vodka=AlfieCocktail+ Sunset + SexOnTheBeach";
const [keys, values] = str
.split(",")
.map((item) => item.split("="))
.reduce(
(acc, item) => [acc[0].concat(item[0]), acc[1].concat(item[1])],
[[], []]
);
console.log(keys, values);

Is there an ES6 method to search an array for elements with elements from another array?

I have two arrays containing some parameter values. All elements in the arrays are strings like the following:
x = [ "vorzugsreihe=J", "nennleistung=94,1127", "nenndrehzahl=31,9400"]
y = ["nenndrehzahl=500,3000"]
Expected Output would be:
x = [ "vorzugsreihe=J", "nennleistung=94,1127", "nenndrehzahl=500,3000"]
I have tried using Array.Filter but can't seem to be able to filter only partially (like starting with the string instead of the whole string since that won't match as the values are different).
What I'd like is to be able to go through each element from array Y, and search if the element(string before "=") exists in array X and replace the value(s) of that element in array X.

for(var i=0;i<x.length;i++){
var currentStr = x[i];
var currentInterestedPart = /(.+)=(.+)/.exec(currentStr)[1];
var replacePart = /(.+)=(.+)/.exec(currentStr)[2];
for(var j=0;j<y.length;j++){
if(!y[j].startsWith(currentInterestedPart)) {continue;}
var innerReplacePart = /(.+)=(.+)/.exec(y[j])[2];
x[i] = currentStr.replace(replacePart,innerReplacePart);break;
}
}
Try this. This makes use of RegEx and it is less error prone.

You can use Map and map
First create a Map from array y, split each element by = use first part as key and second part as value
Loop over x array, split each element by = and use first part as key to search in Map if it's present use value from Map else return without any change
let x = ["vorzugsreihe=J", "nennleistung=94,1127", "nenndrehzahl=31,9400"]
let y = ["nenndrehzahl=500,3000"]
let maper = new Map(y.map(v => {
let [key, value] = v.split('=', 2)
return [key, value]
}))
let final = x.map(v => {
let [key, value] = v.split('=', 2)
if (maper.has(key)) {
return key + '=' + maper.get(key)
}
return v
})
console.log(final)

For each value in the y array, iterate and check if the word exist in the x array. Once you find a match just update the value. (The below solution mutates the original array)
const x = [ "vorzugsreihe=J", "nennleistung=94,1127", "nenndrehzahl=31,9400"],
y = ["nenndrehzahl=500,3000"],
result = y.forEach(word => {
let [str, number] = word.split('=');
x.forEach((wrd,i) => {
if(wrd.split('=')[0].includes(str)) {
x[i] = word;
}
});
});
console.log(x);

I'd suggest using combination of reduce + find - this would accumulate and give you the results you're expecting.
var x = [ "vorzugsreihe=J", "nennleistung=94,1127", "nenndrehzahl=31,9400"]
var y = ["nenndrehzahl=500,3000"]
var combinedArr = x.reduce((acc, elem, index) => {
const elemFoundInY = y.find((yElem) => yElem.split("=")[0] === elem.split("=")[0]);
if (elemFoundInY) {
acc = [...acc, ...[elemFoundInY]]
} else {
acc = [...acc, ...[elem]];
}
return acc;
}, [])
console.log(combinedArr);

You can use .startsWith() to check if element start with key= and then replace its value:
let x = [ "vorzugsreihe=J", "nennleistung=94,1127", "nenndrehzahl=31,9400"];
let y = ["nenndrehzahl=500,3000"];
y.forEach(val => {
let [key, value] = val.split("=");
for (let i = 0; i < x.length; i++) {
if (x[i].startsWith(`${key}=`)) x[i] = `${x[i].split("=")[0]}=${value}`;
}
})
console.log(x)

Try this:
y.forEach(item => {
const str = item.split("=")[0];
const index = x.findIndex(el => el.startsWith(str));
if (index) {
const split = x[index].split('=');
x[index] = `${split[0]}=${split[1]}`;
}
})

JavaScript to split data and calculate sums

I believe what I need are two JavaScript functions. I am receiving a comma separated string that holds two types of data: 1) device name followed by 2) numeric value. These two values are separated by a comma, and each set is also separated by a comma. Example string below:
Device_A,5,Device_C,2,Device_A,10,Device_B,8,Device_B,2,Device_C,7
What I want to do is create two separate functions. The first function finds the unique device names and returns just the names in a comma separated string. The second function would calculate the sum of the numeric values for each device. The expected results from the example string above would return:
Function 1 (Device List):
Device_A, Device_B, Device_C
Function 2 (Sums per Device List):
15,10,9
The lists do not need to return in any particular order as long at they both match up. All I have successfully done at this point is return a list of unique values (including numeric values)... I'm stuck on separating the list, but still referring to device name to sum up all of the values.
Thanks in advance. Let me know if you have any questions!
Matt

You could use an object for collecting the names and count.
This edit contains a shared function and two function for the result in equal order.
function getGrouped(data) {
var array = data.split(','),
temp = Object.create(null),
i = 0;
while (i < array.length) {
temp[array[i]] = (temp[array[i]] || 0) + +array[i + 1] || 0;
i += 2;
}
return temp;
}
function getDevices(data) {
var temp = getGrouped(data);
return Object.keys(temp).sort().join();
}
function getCounts(data) {
var temp = getGrouped(data);
return Object.keys(temp).sort().map(function (k) { return temp[k]; }).join();
}
var data = "Device_A,5,Device_C,2,Device_A,10,Device_B,8,Device_B,2,Device_C,7";
console.log(getDevices(data));
console.log(getCounts(data));

When starting out on a problem like this, I think it's wise to not worry about doing it in a single loop or in a fancy one-liner at first.
A) Start out by defining what data structures you need and how to go from one format to another:
Convert my string of data to a list of keys and values
Somehow group these keys and values based on the key
Sum the values for each group
Return a list of all unique keys
Return a list of all summed values
B) Then, try to see if any of the code you've written has the potential be re-used by other parts of your application and refactor accordingly.
C) Finally, assess if there are performance bottle necks and only if there are, optimize for performance.
A. A function for each step:
// 1. From string to array of keys and values
// You already figured this one out. Split by ","!
const namesAndValuesFromString =
str => str.split(",");
// 2. Grouping by key
// Let's first make pairs:
const deviceValuePairs = devicesAndValues => {
let pair = [];
const pairs = [];
devicesAndValues.forEach(x => {
pair.push(x);
if (pair.length === 2) {
pairs.push(pair);
pair = [];
}
});
return pairs;
};
// Key value pairs are a nice starting point for constructing a grouped object:
const kvpsToDeviceValuesObj = kvps => {
const valuesByDevice = {};
kvps.forEach(([key, value]) => {
value = Number(value);
if (!valuesByDevice[key]) {
valuesByDevice[key] = [];
}
valuesByDevice[key].push(value);
});
return valuesByDevice;
};
// 3. Now, we can get to summing the values arrays
const sumValueArrays = valuesByDevice => {
const summedValuesByDevice = {};
// Loop over the objects entries
Object.entries(valuesByDevice).forEach(
([key, values]) => {
summedValuesByDevice[key] = values
.reduce((a, b) => a + b);
}
);
return summedValuesByDevice;
};
// 4. + 5. Now that we have an object with device ids as keys, and summed values inside, we can retrieve the two lists
const getDevices = Object.keys;
const getSums = Object.values;
// Running the code:
const namesAndValues =
namesAndValuesFromString("A,5,C,2,A,10,B,8,B,2,C,7");
console.log(namesAndValues);
const kvps = deviceValuePairs(namesAndValues);
console.log(kvps);
const valuesByDevice = kvpsToDeviceValuesObj(kvps);
console.log(valuesByDevice);
const sumValues = sumValueArrays(valuesByDevice);
console.log(sumValues);
const devices = getDevices(sumValues);
console.log(devices);
const sums = getSums(sumValues);
console.log(sums);
B. Refactoring!
Once you understand each of those steps, you'll start to see things that can be generalized or combined. That's where the fun starts :)
// UTILITIES
const split = del => arr => arr.split(del);
const toPairs = arr => {
let pair = [];
return arr.reduce(
(pairs, x) => {
pair.push(x);
if (pair.length === 2) {
pairs.push(pair);
pair = [];
}
return pairs;
}, []);
};
const sum = (x, y = 0) => +x + y;
const kvpsToGroups = grouper => kvps =>
kvps.reduce(
(groups, [key, value]) => Object.assign(groups, {
[key]: grouper(value, groups[key])
}), {});
// YOUR APP
const sumGrouper = kvpsToGroups(sum);
const dataSplitter = split(",");
const parseData = str => sumGrouper(toPairs(dataSplitter(str)));
// MAIN
const result = parseData("A,5,C,2,A,10,B,8,B,2,C,7");
console.log("devices:", Object.keys(result));
console.log("sums:", Object.values(result));

another way by regexs
let str = "Device_A,5,Device_C,2,Device_A,10,Device_B,8,Device_B,2,Device_C,7", obj = {}
str.match(/(\w+,[0-9]+)/g).forEach((s) => {
s = s.split(',')
obj[s[0]] = (obj[s[0]] || 0) + (Number(s[1]) || 0)
})
console.log(obj)

Something like this should do it:
var input = "Device_A,5,Device_C,2,Device_A,10,Device_B,8,Device_B,2,Device_C,7";
var output = input.split(',').reduce((accumulator, currentValue, currentIndex, array) => {
accumulator[currentValue] = (accumulator[currentValue] || 0)
+ parseInt(array[currentIndex + 1]);
array.splice(0,1);
return accumulator;
}, {});
console.log(Object.keys(output));
console.log(Object.keys(output).map(k => output[k]));