Kevin Powell - Community•3y ago

compare arrays

Hello, How to : compare arrays how many same values in it? here is an example, but not working: https://codepen.io/lanszelot/pen/PoaEorm the arrays value could be -red red red red- , or -blue red yellow blue- or any variation. if one array have more same value /like red red red/ and the other one have only one red it have to count once only. arrays lenght is same. only the values could be different or equal.

Darth Vader

CodePen

PoaEorm

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16 Replies

13eck•3y ago

Are you looking for a complete match, element by element? Or are you wanting to see if the arrays have the same number of array elements? For example, would any of these pass the test you're trying to write:

// this isn't strictly equal because the elements are in a different order
const arr1 = ["red", "blue", "green", "blue"];
const arr2 = ["blue", "red", "blue", "green"];

// they both have the same content, but not in the same
// quantity
const arr3 = ["red", "blue", "green", "blue"];
const arr4 = ["red", "red", "blue", "green"];

// these have the same elements in the same
// quantity and same place
const arr5 = ["red", "blue", "green", "blue"];
const arr6 = ["red", "blue", "green", "blue"];

// this isn't strictly equal because the elements are in a different order
const arr1 = ["red", "blue", "green", "blue"];
const arr2 = ["blue", "red", "blue", "green"];

// they both have the same content, but not in the same
// quantity
const arr3 = ["red", "blue", "green", "blue"];
const arr4 = ["red", "red", "blue", "green"];

// these have the same elements in the same
// quantity and same place
const arr5 = ["red", "blue", "green", "blue"];
const arr6 = ["red", "blue", "green", "blue"];

Which are you looking for?

lanszelotOP•3y ago

no, í do not want to compare the arrays. I want to compare the values. How many same values in the arrays so all of them the arrays are changeing all the time, and the arrays lenght too.

MarkBoots•3y ago

maybe there is an easier, better way, but would this do it? (first thing that came to mind)

[...new Set(aTomb)].reduce((a, c) => a + [...new Set(bTomb)].includes(c), 0)

[...new Set(aTomb)].reduce((a, c) => a + [...new Set(bTomb)].includes(c), 0)

lanszelotOP•3y ago

so array lenght could be 4 or 3 or 2 , but both have same lenght

13eck•3y ago

~~If "all of them" then your code looks like it works~~ Igonre that, I'm wrong

MarkBoots•3y ago

i think he's looking for the unique values that are present in both arrays ??

13eck•3y ago

Mark is right, create a new Set() for each to remove duplicates and compare the length of each also

lanszelotOP•3y ago

I am testing Mark´s code. It looks good for a first sight. But I have to test it. Thanks for the help . It takes a few minutes while I testing

MarkBoots•3y ago

ah, i think im not right. the first example has 2 duplicates in both arrays and they still return 4. Not sure about the task now

lanszelotOP•3y ago

your code looks right. I put it end of the line - on the link what I shared. be carefull , all 3 code have own arrays so your code starting after 14th line with new arrays and it is good but I have to test with more arrrays

MarkBoots•3y ago

yea, okay. but with my code the first will also return 3. is that correct?

lanszelotOP•3y ago

your code return 3rd number which is 3. If you check the arrays the 17th line have "red" which is not in the 16th, so 3 is perfect return

MarkBoots•3y ago

okay... just asking. thought it had to be the same code for all examples

lanszelotOP•3y ago

I separated with comments 🙂

MarkBoots•3y ago

okay you can remove the " + " before " a " btw. that was a typo

lanszelotOP•3y ago

It is working well. Thank you so much 🙂

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compare arrays