I have an array with values
myarray=["Mark:40", "John:20", "Sofia: 60", "Mark:30"]
desiredArray=["Mark:70", "John:20", "Sofia: 60"]
It should check whether the names are unique and if it found same name multiple times, it should add the marks and make the desired array with distinct elements. I am able to get unique array but not able to merge the marks. Could anyone help?
You could take a Map for collecting the values and render new strings for the result.
var array = ["Mark:40", "John:20", "Sofia: 60", "Mark:30"],
result = Array.from(
array.reduce(
(m, s) => (([k, v]) => m.set(k, (m.get(k) || 0) + +v))(s.split(/:\s*/)),
new Map
).entries(),
a => a.join(':')
);
console.log(result);
You can group the array by using reduce. Use Object.entries to convert the object into an array and map to form the desired output.
let myarray = ["Mark:40", "John:20", "Sofia: 60", "Mark:30"];
let desiredArray = Object.entries(myarray.reduce((c, v) => {
let [n, a] = v.split(':');
c[n] = c[n] || 0;
c[n] += +a;
return c;
}, {})).map(o => o[0] + ":" + o[1]);
console.log(desiredArray);
You can choose to go with simple for loop also:
var myarray=["Mark:40", "John:20", "Sofia: 60", "Mark:30"];
for(var i=0; i<myarray.length; i++){
var splitVal = myarray[i].split(":");
var nameI = splitVal[0];
var scoreI = parseInt(splitVal[1]);
for(var j=i+1; j<myarray.length; j++){
splitVal = myarray[j].split(":");
var nameJ = splitVal[0];
if(nameI === nameJ){
scoreI += parseInt(splitVal[1]);
myarray.splice(j,1);
}
}
myarray[i] = nameI+":"+scoreI;
}
console.log(myarray);
A simple approach would be to iterate over the new array every time that you would like to add a new value and check whether or not the key exists. If it does increment the value, if not add it.
Here is one solution with a temporary object.
// Initial array
const myarray = ["Mark:40", "John:20", "Sofia: 60", "Mark:30"]
// Temporary object used to calculate values
const desired = {};
for (let value of myarray) {
// Index of the first digit in the string
const separatorIndex = value.indexOf(':') + 1;
// Key is everything before the first digit including the :
let key = value.substr(0, separatorIndex);
// If the key isn't present in the object add it
if (desired[key] === undefined) {
desired[key] = 0;
}
// Add the value of the key to the temporary object
// this combines the values of equal keys
desired[key] += parseFloat(value.substr(separatorIndex));
}
const desiredArray = [];
// Create an array from all values
for (let key in desired) {
desiredArray.push(key + desired[key].toString());
}
console.log(desiredArray);
You can do:
const array = ["Mark:40", "John:20", "Sofia: 60", "Mark:30"];
const temp = array.reduce((a, c, i, arr) => {
const u = c.split(':');
a[u[0]] = a[u[0]] + +u[1] || +u[1];
return a;
}, {});
const result = Object.keys(temp)
.map(u => `${u}:${temp[u]}`);
console.log(result);