I have an array of integers. How can a determine a value's index depending on array, if I was to insert it into the array, so that no value before it is bigger.
Example:
let value = 3941;
calcOrder(value);
calcOrder(value) {
let array = [3002,2934, 1044, 2848, 1293, 9342, etc..]
// some logic
}
}
Result: According to this example, my function should return 5 ( cause 3941 < 9342 but more than other values in array ).
You can use .filter() method of arrays:
let value = 3941,
array = [3002,2934, 1044, 2848, 1293, 9342];
let result = array.filter(v => v < value).length;
console.log(result);You can write a loop to check the logic and count the numbers using length
DEMO
function countOthers(value) {
return function(element, index, array) {
return (element < value);
}
}
var filtered = [3002,2934, 1044, 2848, 1293, 9342].filter(countOthers(3941)).length;
console.log(filtered);You can use filter() to get the array of all the elements which are less than the value. Finally take the length of the array:
let value = 3941;
console.log(calcOrder(value));
function calcOrder(value) {
let array = [3002,2934, 1044, 2848, 1293, 9342]
return array.filter(i => i<value).length;
}You can use Array.forEach() to loop over the array and increase the count value if the number is less than the value:
let value = 3941;
function calcOrder(value) {
let array = [3002, 2934, 1044, 2848, 1293, 9342]
let count = 0;
array.forEach((item) => {
if (item < value) {
count++;
}
});
return count;
}
console.log(calcOrder(value));You can use old way to get that result without using array functions to make it work in IE browsers and older versions of web browsers:
let value = 3941;
function calcOrder(value) {
let array = [3002, 2934, 1044, 2848, 1293, 9342]
let count = 0;
array.forEach(function(item){
if (item < value) {
count++;
}
});
return count;
}
console.log(calcOrder(value));For an O(n) solution that doesn't require creating an intermediate array, use reduce: start at 0, add one to the accumulator when the item you're iterating over is smaller than the value whose position you're looking for:
const array = [3002,2934, 1044, 2848, 1293, 9342];
const calcOrder = value => array.reduce((a, num) => num < value ? a + 1 : a, 0);
console.log(calcOrder(3941));
It could be a "sort" and "findIndex" logic.
var array = [3002,2934, 1044, 2848, 1293, 9342]
var calOrder = (num) => ((index = array.sort().findIndex(val => val > num)), index == -1 ? array.length : index)
calOrder(3941) // 5
forloop with some basic math operations...[10000, 3002,2934, 1044, 2848, 1293, 9342, 1]?