Remove duplicate substring in an array

Question

I have an array like below:

[
  'author/2020/01/01/all_authors_000.csv',
  'book/2020/01/01/all_books_000.csv',
  'book/2020/01/01/all_books_001.csv',
  'book/2020/01/01/all_books_002.csv',
  'others/2020/01/01/other_stuff.csv',
]

As you can see there are three items that start with the word book. I want to remove all but one, so I end up with something like:

[
  'author/2020/01/01/all_authors_000.csv',
  'book/2020/01/01/all_books_000.csv',
  'others/2020/01/01/other_stuff.csv',
]

How can I achieve this?

Technically your question says ***Remove duplicate substring in an array*** and there is no duplicate. — Manas Khandelwal, Mar 22 '21 at 07:25
what is the criteria. are `book/2020` and `book/2021` also dublicates? — eamanola, Mar 22 '21 at 07:32

Daweed · Answer 1 · 2021-03-22T07:37:51.623

3

Here is working example:

var array = [
   "author/2020/01/01/all_authors_000.csv",
   "book/2020/01/01/all_books_000.csv",
   "book/2020/01/01/all_books_001.csv",
   "book/2020/01/01/all_books_002.csv",
   "others/2020/01/01/other_stuff.csv",
];

var filteredArray = [];
var previous = "";

for (let i of array) {
   if (i.substr(0, i.indexOf("/")) != previous) {
      filteredArray.push(i);
      previous = i.substr(0, i.indexOf("/"));
   }
}

Every loop the value before "/2020" is stored inside the previous variable, and the if statement checks, if the value is the same as in the previous loop. If not, it pushes it into the filteredArray.

Therefore filteredArray is the array without duplicates.

edited Mar 22 '21 at 07:37

answered Mar 22 '21 at 07:33

Daweed

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thank you. do you know if this can also be achieved by lodash? – blankface Mar 22 '21 at 07:37
@blankface I don't have experience with lodash myself, but take a look at [this](https://stackoverflow.com/questions/31740155/lodash-remove-duplicates-from-array). – Daweed Mar 22 '21 at 07:39

score 0 · Answer 2 · answered Mar 22 '21 at 07:57

Here is another method of doing it. Basically a function that takes in your array and a criteria to identify duplicates (in your case book). All of these duplicates will be removed but the first one.

const array = [
  "author/2020/01/01/all_authors_000.csv",
  "book/2020/01/01/all_books_000.csv",
  "book/2020/01/01/all_books_001.csv",
  "book/2020/01/01/all_books_002.csv",
  "others/2020/01/01/other_stuff.csv",
];

const removeDuplicates = (array, criteria) => {
  return array.filter(
    (path) =>
      ![...array.filter((path) => path.includes(criteria)).splice(1)].includes(
        path
      )
  );
};

console.log(removeDuplicates(array, "book"));

Remove duplicate substring in an array

2 Answers2