Top "Duplicates" questions

The "duplicates" tag concerns detecting and/or dealing with multiple instances of items in collections.

How to delete duplicates on a MySQL table?

I need to DELETE duplicated rows for specified sid on a MySQL table. How can I do this with an …

mysql duplicates
How do I remove duplicate items from an array in Perl?

I have an array in Perl: my @my_array = ("one","two","three","two","three"); How do I remove the duplicates …

perl arrays unique duplicates
How to find duplicate records in PostgreSQL

I have a PostgreSQL database table called "user_links" which currently allows the following duplicate fields: year, user_id, sid, …

sql postgresql duplicates
Does adding a duplicate value to a HashSet/HashMap replace the previous value

Please consider the below piece of code: HashSet hs = new HashSet(); hs.add("hi"); -- (1) hs.add("hi"); -- (2) hs.…

java hashmap duplicates hashset
Algorithm: efficient way to remove duplicate integers from an array

I got this problem from an interview with Microsoft. Given an array of random integers, write an algorithm in C …

c algorithm arrays duplicates
python pandas: Remove duplicates by columns A, keeping the row with the highest value in column B

I have a dataframe with repeat values in column A. I want to drop duplicates, keeping the row with the …

python duplicates pandas
Left Join without duplicate rows from left table

Please look at the following query: tbl_Contents Content_Id Content_Title Content_Text 10002 New case Study New case Study 10003 …

sql join duplicates
How to get duplicate items from a list using LINQ?

I'm having a List<string> like: List<String> list = new List<String>{"6","1","2","4","6","5","1"}; I need …

c# linq duplicates
Is there a no-duplicate List implementation out there?

I know about SortedSet, but in my case I need something that implements List, and not Set. So is there …

java list collections duplicates
How to remove duplicates from a list?

I want to remove duplicates from a list but what I am doing is not working: List<Customer> …

java list collections duplicates