Get unique value by comparing 2 arrays

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CK Ng

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Jun 21, 2022, 9:16:11 PMJun 21
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Hi, im new for apps script, i would like to ask how to get the unique value by comparing 2 arrays, for example array1 is [ab,abc,abcd,def,defg], array2 is [abc,abcd,defg], i want to compare this 2 arrays and then get the value that doesnt exist in both array('ab' and 'def').

Appreciate for help.

R Tichy

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Jun 21, 2022, 10:34:41 PMJun 21
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let a = ['ab', 'abc', 'abcd', 'def', 'defg']
let b = ['abc', 'abcd', 'defg'];
var result = [];
Logger.log(a, b, result)
a.forEach( function(each){
   if (!b.includes(each)) { result.push(each);
}});
b.forEach(function(each){
   if (!a.includes(each)) { result.push(each);}
});
Logger.log(result);
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dimud...@gmail.com

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Jun 22, 2022, 6:08:38 AMJun 22
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You're looking for a 'diff' algorithm; ie. the difference of two sets returns the values that are not common to both.

There are lots of implementations out there on the web but some are more performant than others.

If performance is paramount, your best bet is to use libraries like Lodash or Ramda (granted, porting libraries to GAS can be difficult but I believe there is a lodash port available for GAS).

If you value readability over performance check out the code from the article linked below on set operations in modern Javascript:

https://2ality.com/2015/01/es6-set-operations.html

Keith Andersen

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Jun 22, 2022, 10:57:01 AMJun 22
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let a = ['ab', 'abc', 'abcd', 'def', 'defg']
let b = ['abc', 'abcd', 'defg'];

let result = a.concat(b);

//console.log(result);

let uniqueArray = result.filter((item, index) => result.indexOf(item) === index);

uniqueArray.sort();

console.log(uniqueArray);


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Bruce Mcpherson

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Jun 22, 2022, 11:28:54 AMJun 22
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const x = () => {
const a1 = [1,2,3,4,9,20]
const a2 = [2,20,3,4,8,7]

// a)
const resulta = a1.concat(a2).filter(f=>!(a2.includes(f)&&a1.includes(f)))
// [1,9,8,7]
console.log(resulta)

// b)
const a1Set = new Set(a1)
const a2Set = new Set(a2)

const resultb = a1.filter(f=>!a2Set.has(f)).concat(a2.filter(f=>!a1Set.has(f)))
// [1,9,8,7]
console.log(resultb)

}

On Wed, 22 Jun 2022 at 02:16, CK Ng <ckng...@gmail.com> wrote:
Hi, im new for apps script, i would like to ask how to get the unique value by comparing 2 arrays, for example array1 is [ab,abc,abcd,def,defg], array2 is [abc,abcd,defg], i want to compare this 2 arrays and then get the value that doesnt exist in both array('ab' and 'def').

Appreciate for help.

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