As the title suggests, I want to create a function the counts the number of values in my array between two values that have been entered by the user. So for example, if the array was [1, 4, 6, 7, 8, 6] and the user entered 5 as their first value and 7 as their second value, they would be greeted with an alert that said
"total number of values = 3".
All you need is a simple for loop.
var total = 0;
var num1 = 5;
var num2 = 7;
var array = [1,4,6,7,8,6];
for(var a = 0; a < array.length; a++) {
if(array[a] >= num1 && array[a] <= num2) {
total++;
}
}
alert("Total numbers of values = " + total);
This will loop through the array, detect nums within the range, tally up a value, and output it in a alert.
You can create an extremely clean solution to this problem by utilizing the second property of Array#filter (which sets the this binding given to your callback of choice):
var array = [1, 4, 6, 7, 8, 6]
function inRange (x) {
return this[0] <= x && x <= this[1]
}
var result = array.filter(inRange, [5, 7]).length
console.log('Total number of values:', result)You can use Array.prototype.filter(), RegExp.prototype.test() with RegExp constructor with class from-to, where from is 5, to is 7, get .length of resulting array
var from = 5;
var to = 7;
var len = arr.filter(RegExp.prototype.test.bind(new RegExp(`[${from}-${to}]`))).length;
You can alternatively use .toString(), .match()
var arr = [1,4,6,7,8,6];
var from = 5;
var to = 7;
var res = arr.toString().match(new RegExp(`[${from}-${to}]`, "g"));
var len = res.length;
console.log(res.length);
"5" and "17"?
var len = arr.filter(n => n >= from && n <= to).length;
arr.filter(/./.test, RegExp(`[${from}-${to}]`, "g")) is simplerRegExp constructor is set to this within .filter(), yes? What is purpose for /./? Same as RegExp.prototype?/./.test passes the generic .test() rx method, the 2nd argument tells that method what this is. simpler example: filter for even integers: [0,1,2,3,4].filter(/./.test, /[02468]$/) or find Capitals: [].filter.call("Dan Davis", /./.test, /[A-Z]$/)You may do as follows;
var arr = [1,4,6,7,8,6],
input = [5,7],
result = arr.reduce((r,n) => n >= input[0] && n <= input[1] ? ++r : r, 0);
console.log(result);
var array = [1, 4, 6, 7, 8, 6];
function countNumber(arr,a,b){
let count = 0;
for (const number of arr){
if (number >= a && number <= b){
count ++;
}
}
return count;
}
console.log(countNumber(array, 5, 7));
forloop containing anifstatement... (Or if you want to get "fancy", you could use the array.reduce()method.)9?