How to get value at highest index in a array from the values of another array with javascript programming [closed]
I have 2 set of array
var A = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L"];
var B = ["B", "J", "A", "C", "G"];
now I have to a value from var B which is at highest index in var A, it is J
I have to find out J in var B by JavaScript programming
Thanks in advance
Answers:
Sort the second array in descending order and then find the element by iterating. You can use sort() for sorting descending order and find() for getting the element.
var A = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L"],
B = ["B", "J", "A", "C", "G"];
function customArrayFunction(A, B) {
// create an additional array variable for storing sorted array, otherwise it will update the order of array B
var sortB = [];
B.forEach(function(v) {
sortB.push(v);
});
// sorting array on descending order
// instead of custom compare function
// you can use `sortB.sort().reverse()` simply
var res = sortB.sort(function(a, b) {
if (a > b)
return -1;
else if (a < b)
return 1;
return 0;
})
// finding element
.find(function(v) {
return A.indexOf(v) > -1;
});
return res;
}
console.log(customArrayFunction(A,B));
console.log(customArrayFunction(["A","D","G"],["B","D","G"]));Using ES6 arrow function
var A = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L"],
B = ["B", "J", "A", "C", "G"];
function customArrayFunction(A, B) {
var sortB = [];
B.forEach(v => sortB.push(v));
var res = sortB.sort((a, b) => {
if (a > b)
return -1;
else if (a < b)
return 1;
return 0;
}).find(v => A.indexOf(v) > -1);
return res;
}
console.log(customArrayFunction(A, B));
console.log(customArrayFunction(["A", "D", "G"], ["B", "D", "G"]));More easiest way without using any custom compare function with help of reverse(), which helps to reverse the array.
var A = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L"],
B = ["B", "J", "A", "C", "G"];
function customArrayFunction(A, B) {
var sortB = [];
B.forEach(v => sortB.push(v));
var res = sortB.sort()
.reverse()
.find(v => A.indexOf(v) > -1);
return res;
}
console.log(customArrayFunction(A, B));
console.log(customArrayFunction(["A", "D", "G"], ["B", "D", "G"]));UPDATE : If you want to search based on the index then there is no need of sort , just use find()
var A = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L"],
B = ["B", "J", "A", "C", "G"];
function customArrayFunction(A, B) {
var res = A
.find(v => B.indexOf(v) > -1);
return res;
}
console.log(customArrayFunction(A, B));
console.log(customArrayFunction(["A", "D", "G"], ["B", "D", "G"]));use forEach of list to get your desired result.
var A = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L"];
var B = ["B", "J", "A", "C", "G"];
var index = -1; // find index of your array A
A.forEach(function(item1, index1) {
B.forEach(function(item2, index2) {
if (item1 === item2) {
index = index1 > index ? index1 : index;
}
})
})
var result = index >= 0 ? A[index] : 'No Result found'; // gives your desired result.
might be a little too low tech, but what about the following(console.logging it for testing purposes)
var A = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L"];
var B = ["B", "J", "A", "C", "G"];
var max=0;
var letter="";
for(i=0;i<B.length;i++)
{
var test=A.indexOf(B[i]);
if(test > max){max=test;letter=B[i]};
}
console.log(letter)
console.log give "J" as expected
This is a solution with a temporary object and some array methods.
var a = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L"],
b = ["B", "J", "A", "C", "G"],
result = function (array1, array2) {
var o = {},
r;
array2.forEach(function (a) {
o[a] = true;
});
a.reverse().some(function (a) {
if (o[a]) {
r = a;
return true;
}
});
return r;
}(a, b);
document.write(result);