how to single out an element in two array's [duplicate] - javascript

This question already has answers here:
How to get the difference between two arrays in JavaScript?
(84 answers)
Closed 6 years ago.
Say I have 2 arrays:
var array1 = [1, 2, 3];
var array2 = [1, 2, 3, 4];
How do I compare them to single out the element ( in this case the number 4 )?
Something like:
if ( array1 == array2 ) {
//then do this
}else{
// find out the one that isn't the same in each and show it here
}

You can use Array.prototype.find to do the same
check this snippet
var array1 = [1, 2, 3];
var array2 = [1, 2, 3, 4];
function findNumber(number) {
return number=== 4?true:false;
}
var number=array2.find(findNumber);
if(number)
console.log("found");
else
console.log("not found");
Hope it helps

Related

Hello everyone, I am working through a program and stuck on a challenge and cannot figure out why this will not work [duplicate]

This question already has answers here:
How are for loops executed in javascript?
(6 answers)
Closed last year.
Task: Use a for loop to iterate through the array and increase each number by two.
const increaseByTwo = [1, 2, 3, 4, 5];
What is wrong with my code here?
for (let i = 0; i < increaseByTwo.length; i+=2){
}
is this what you need?
const increaseByTwo = [1, 2, 3, 4, 5];
var newArr = [];
increaseByTwo.forEach(e=>newArr.push(e+2))
console.log(newArr)

Javascript, convert an array of double into an array of pair of doubles [duplicate]

This question already has answers here:
Split array into chunks
(73 answers)
Closed 2 years ago.
Suppose that you have an array of doubles in Javascript:
double_arr = [1, 2, 3, 4, 5, 6, 7, 8]
What is the most efficient way to convert it into an array of arrays with 2 doubles like above:
double_arr = [[1,2], [3,4], [5,6], [7,8]]
You can iterate skipping one index in each iteration, like this:
const double_arr = [1, 2, 3, 4, 5, 6, 7, 8];
const result = [];
for (let i = 0; i < double_arr.length; i += 2)
result.push([ double_arr[i], double_arr[i+1] ]);
console.log(result);

How to find common elements only between 2 arrays in Angular 2 [duplicate]

This question already has answers here:
Simplest code for array intersection in javascript
(40 answers)
Compute intersection of two arrays in JavaScript [duplicate]
(4 answers)
Closed 5 years ago.
var array1 = [1, 2, 3, 4, 5, 6];
var array2 = [1, 2, 3, 4, 5, 6, 7, 8, 9];
1.)If elements are equals,show that common elemenst in output
2.)The output(common elements) should be array form
Use Array#filter method and inside filter function use Array#indexOf or Array#includes methods to check second array includes the element.
var array1 = [1, 2, 3, 4, 5, 6];
var array2 = [1, 2, 3, 4, 5, 6, 7, 8, 9];
var res = array1.filter(function(v) { // iterate over the array
// check element present in the second array
return array2.indexOf(v) > -1;
// or array2.includes(v)
})
console.log(res);

I want to remove all the item in the array except the last item push in the array [duplicate]

This question already has answers here:
Get the last item in an array
(59 answers)
Closed 5 years ago.
This is the example of the array
arr = [1,2,3,4,5];
I expect to have this kind of result
arr = [5];
Use Splice/Slice function as below:
var arr = [1, 2, 3, 4, 5];
arr = arr.slice(-1);
console.log(arr);
OR
var arr = [1, 2, 3, 4, 5];
arr = arr.splice(arr.length - 1,1);
console.log(arr);

Merge two arrays in javascript [duplicate]

This question already has answers here:
How to merge two arrays in JavaScript and de-duplicate items
(89 answers)
Closed 9 years ago.
I know in PHP I can use the array_merge function to do this, but let's say I have two arrays like this:
var arr1 = [1, 2, 3];
var arr2 = [4, 5, 6];
How do I merge these two arrays into another array arr3 so that it looks like this:
var arr3 = [1, 2, 3, 4, 5, 6];
Thank you
Try this
var arr1 = [1, 2, 3];
var arr2 = [4, 5, 6];
var array3 = arr1.concat(arr2 );

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