How do I remove duplicates from a structure array?

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Craig
Craig am 16 Mai 2013
Kommentiert: John King am 5 Mai 2021
Suppose I create the following structure:
animals(1).name='Northern Mockingbird';
animals(1).class='Bird';
animals(2).name='Cheetah';
animals(2).class='mammal';
animals(3).name='Wolf';
animals(3).class='mammal';
animals(4).name='Eagle';
animals(4).class='Bird';
animals(5).name='Turtle';
animals(5).class='Reptile';
animals(6).name='Bee';
animals(6).class='Insect';
animals(7).name='Chameleon';
animals(7).class='Reptile';
animals(8).name='Barn Spider';
animals(8).class='Arachnid';
animals(9).name='Ant';
animals(9).class='Insect';
animals(10).name='Northern Cardinal';
animals(10).class='Bird';
Then I set animals(11) equal to animals(4), then I sort the whole thing through a littany of conversions/reshapings, the sortrows command and another littany of conversions/reshapings.
Is there some way to remove the duplicate entries from that array of structures?

Akzeptierte Antwort

Azzi Abdelmalek
Azzi Abdelmalek am 16 Mai 2013
Bearbeitet: Azzi Abdelmalek am 16 Mai 2013
a= {animals.name}
b= {animals.class}
c=cellfun(@(x,y) [x y],a', b','un',0)
[ii,ii]=unique(c,'stable')
animals=animals(ii)
  2 Kommentare
Azzi Abdelmalek
Azzi Abdelmalek am 16 Mai 2013
Bearbeitet: Azzi Abdelmalek am 16 Mai 2013
%or
[ii,ii]=unique({animals.name},'stable')
animals=animals(ii)
Because if the name is the same, the class should be the same.
Craig
Craig am 17 Mai 2013
Agreed. The actual structure array is file names and their respective paths; I used the animal array because it is easier to check, the difference (that I had not thought of) is that there could be files that have identical names but reside in different folders. Since your first solution looks for unique name/class pairs (through concatenation), it will still work for file names and paths.
'c=cellfun(@(x,y) [x y],a', b','un',0)' was baffling to me. I sort of understand the 'cellfun' and am slowly getting acquainted with the '@' symbol, but the '(x,y) [x y]' part was confusing to me at first. I think I get it now though. I couldn't find the 'un' property in the documentation; is it the same as 'UniformOutput'?

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Weitere Antworten (1)

Jonathan Sullivan
Jonathan Sullivan am 16 Mai 2013
It's not pretty, but this should work:
isUnique = true(size(animals));
for ii = 1:length(animals)-1
for jj = ii+1:length(animals)
if isequal(animals(ii),animals(jj))
isUnique(ii) = false;
break;
end
end
end
animals(~isUnique) = [];
  2 Kommentare
Craig
Craig am 17 Mai 2013
Thanks for the quick answer. I was hoping to avoid for loops, though I will admit that the loops you came up with are way prettier than I had thought a for loop solution would look like.
John King
John King am 5 Mai 2021
Wow, only had to schange the name from "animals" to my struct name and this worked for me! Thank you Jonathan!

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