topic Re: How to remove duplicate entries from a list? in Discussions

How to remove duplicate entries from a list?

Neo — Thu, 09 Nov 2023 17:02:20 GMT

If I have a list like

myList  = {"John", "Dan", "Rob", "Rob", "Matt", "Shane", "Matt", "Shane", "John"};

How do I get a list with duplicate entries removed ?

myList_new= {"John", "Dan", "Rob", "Matt", "Shane"};

Re: How to remove duplicate entries from a list?

jthi — Thu, 09 Nov 2023 17:09:59 GMT

If it doesn't matter that order changes you can use associative array

Names Default To Here(1);

myList  = {"John", "Dan", "Rob", "Rob", "Matt", "Shane", "Matt", "Shane", "John"};
my_list = Associative Array(myList) << get keys;

Re: How to remove duplicate entries from a list?

hogi — Thu, 09 Nov 2023 17:33:51 GMT

Unfortunately, Associative Arrays get slow if the list is long.

There are other approaches like Summarize and Tables/Summary which are way faster.

So, sometimes it could make sense to create a data table, fill a new column with the list values and use the fast table functions.

Best:
go to and support @jthi 's wish with a Kudo :)