Table Find Duplicate Rows (double, char, datetime)

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Dave
Dave el 25 de Oct. de 2021
Respondida: Abdul Rehan Khan el 12 de Feb. de 2025 a las 20:47
Hello, in table A with 100,000 rows and 40 columns, is there a way to find duplicate rows?
The elements are of the type: double, char, datetime
Thanks

Respuestas (2)

the cyclist
the cyclist el 25 de Oct. de 2021
You might need to share some more details about your table, but you should be able to use the unique function.
% Make some pretend data, which is 8 rows with 4 unique ones
tbl = array2table([magic(4); magic(4)]);
% Find the unique rows, along with indices for identifying the duplicates
[uniqueTableRows,indexToUniqueRows,indexBackFromUnique] = unique(tbl);
See the documentation for details on the indices that are reported.
  2 comentarios
Dave
Dave el 26 de Oct. de 2021
Editada: Dave el 26 de Oct. de 2021
The table has double in some columns, char in some columns, datetime in one column
If I use unique it brings the same number of rows (and I check in excel that some rows are identical)
the cyclist
the cyclist el 26 de Oct. de 2021
Editada: the cyclist el 26 de Oct. de 2021
Different data types should not be a problem with this method:
% Make some pretend data of different types
n = [1; 2; 1; 1; 2; 1];
c = {'a';'b';'a';'b';'a';'b'};
t = datetime({'2014-05-26';'2014-08-03';'2014-05-26';'2014-08-03';'2014-05-26';'2014-08-03'},'InputFormat','yyyy-MM-dd');
% Put them in a table
tbl = table(n,c,t)
tbl = 6×3 table
n c t _ _____ ___________ 1 {'a'} 26-May-2014 2 {'b'} 03-Aug-2014 1 {'a'} 26-May-2014 1 {'b'} 03-Aug-2014 2 {'a'} 26-May-2014 1 {'b'} 03-Aug-2014
% Find the unique rows, along with indices for identifying the duplicates
[uniqueTableRows,indexToUniqueRows,indexBackFromUnique] = unique(tbl)
uniqueTableRows = 4×3 table
n c t _ _____ ___________ 1 {'a'} 26-May-2014 1 {'b'} 03-Aug-2014 2 {'a'} 26-May-2014 2 {'b'} 03-Aug-2014
indexToUniqueRows = 4×1
1 4 5 2
indexBackFromUnique = 6×1
1 4 1 2 3 2

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Abdul Rehan Khan
Abdul Rehan Khan el 12 de Feb. de 2025 a las 20:47
Apart from the indices, how can store the duplicate data in a seperate table?

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