how to create new array with cumulative numbers last index to next cumulative first index.
I have an array-like
const numbers = [ '1', '2', '3', '16', '17', '18', '19', '31', '32', '42', '43', '53', '54', '58', '59', '69', '70', '81', '82', '103', '104', '115', '116']
The expected output will be like
const newArray = [['3', '16'], ['19','31'], ['32','42'], ['43', '53'] ... ]
There is always at least two cumulative number. I tried
const numbers = ['1', '2', '3', '16', '17', '18', '19', '31', '32', '42', '43', '53', '54', '58', '59', '69', '70', '81', '82', '103', '104', '115', '116']
const reGroup = []
const findGroup = numbers.reduce((prev, current) => {
data = []
if (prev == (current - 1)) {
data.push(prev, current)
}
reGroup.push(data)
})
console.log(reGroup)A forEach loop should do. You just have to keep the previous number on hand for comparison.
See comments within the code below.
const numbers = [ '1', '2', '3', '16', '17', '18', '19', '31', '32', '42', '43', '53', '54', '58', '59', '69', '70', '81', '82', '103', '104', '115', '116']
let previous = 0;
let result = [];
// Loop though each array item
numbers.forEach(number => {
// Have it as a number
number = parseInt(number);
// If the previous number + 1 does not equal this one
if (previous + 1 != number) {
// Push a sub array containing the previous number and this one (to string)
result[result.length] = [previous.toString(), number.toString()];
}
// Save the current number for the next iteration
previous = number;
});
/* The expected output will be like
[['3', '16'], ['19','31'], ['32','42'], ['43', '53'] ... ]
*/
console.log(result);const numbers = ['1', '2', '3', '16', '17', '18', '19', '31', '32', '42', '43', '53', '54', '58', '59', '69', '70', '81', '82', '103', '104', '115', '116']
let newArray = []
for(i=0; i < numbers.length; i+=2){
const element = numbers.slice(0 + i, i +2)
newArray.push(element)
}
console.log(newArray)
0: (2) ['1', '2']
1: (2) ['3', '16']
2: (2) ['17', '18']
3: (2) ['19', '31']
4: (2) ['32', '42']
5: (2) ['43', '53']
6: (2) ['54', '58']
7: (2) ['59', '69']
8: (2) ['70', '81']
9: (2) ['82', '103']
10: (2) ['104', '115']