duplicates

I want to find the indices all the rows of a matrix which have duplicates. For example A = [1 2 3 4 1 2 3 4 2 3 4 5 1 2 3 4 6 5 4 3] The vector to be returned would be [1,2,4] A lot of similar questions suggest using the unique function, which I've tried but the closest I can get to what I want is: [C, ia, ic] = unique(A, 'rows') ia = [1 3 5] m = 5; setdiff(1:m,ia) = [2,4] But using unique I can only extract the 2nd,3rd,4th...etc instance of a row, and I need to also obtain the first. Is there any way I can do this? NB: It must be a method which doesn't involve looping through the rows, as I'm

(postgresql) I was trying to COPY csv data into a table but I was getting duplicate key violation errors, and there's no way to tell COPY to ignore those, so following internet wisdom I tried adding this rule: CREATE OR REPLACE RULE ignore_duplicate_inserts AS ON INSERT TO mytable WHERE (EXISTS ( SELECT mytable.id FROM mytable WHERE mytable.id = new.id)) DO NOTHING; to circumvent the problem, but I still get those errors - any ideas why ? Rules by default add things to the current action : Roughly speaking, a rule causes additional commands to be executed when a given command on a given table

I'm having problems with a duplicate tab on Chrome (session's stuff) and I'd like to avoid the action of duplicating tabs (or lacking that close the duplicate one). I'm opening the tab as it was a popup, with no address bar, no status bar, and no nothing, just the window. There's no way to duplicate a tab (opened as a popup) in IE and Firefox (at least I havent found one), but in chrome is still possible. I also know I'm not able to programmatically check if there's an already open duplicated tab Any idea how to approach this? thanks! JosiahDaniels Goal Just to clarify: The goal is to is to

I know my title is not much self-explanatory but let me try to explain it here. I have a file name test.txt which has some duplicate lines. Now, what I want to do is remove those duplicate lines and at the same time update test.txt with the new content. test.txt AAAA BBBB AAAA CCCC I know I can use sort -u test.txt to remove the duplicates but to update the file with new content how do I redirect it's output to the same file. The below command doesn't work. sort -u test.txt > test.txt So, why the above command is not working and whats the correct way? Also is there any other way like sort_and

Consider the following dataframe import pandas as pd df = pd.DataFrame({'A' : [1, 2, 3, 3, 4, 4, 5, 6, 7], 'B' : ['a','b','c','c','d','d','e','f','g'], 'Col_1' :[np.NaN, 'A','A', np.NaN, 'B', np.NaN, 'B', np.NaN, np.NaN], 'Col_2' :[2,2,3,3,3,3,4,4,5]}) df Out[92]: A B Col_1 Col_2 0 1 a NaN 2 1 2 b A 2 2 3 c A 3 3 3 c NaN 3 4 4 d B 3 5 4 d NaN 3 6 5 e B 4 7 6 f NaN 4 8 7 g NaN 5 I want to remove all rows which are duplicates with regards to column 'A' 'B' . I want to remove the entry which has a NaN entry (I know that for all dulicates there will be a NaN and a not- NaN entry). The end results