# How do I sort an array according to the first column?

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lil brain on 28 Jul 2022
Commented: lil brain on 28 Jul 2022
Hi,
I have a cell array which I would like to sort according to the first column. But when I try using
high_emp_sort = sort(high_empathy_ID_factors);
% or
high_emp_sort = sortrows(high_empathy_ID_factors);
... then I only get back errors. Could somebody kindly help?
Jeff

Image Analyst on 28 Jul 2022
Edited: Image Analyst on 28 Jul 2022
Did you mean by the first numerical column? Like this:
%====================================================================================
ca = storedStructure.high_empathy_ID_factors;
data = cell2mat(ca(:, 2:end))
data = 17×4
18 12 14 16 17 19 15 11 8 18 14 22 25 11 17 7 16 22 9 5 11 13 14 10 13 23 16 19 10 18 17 25 9 14 14 15 15 18 17 10
fprintf('Read %d rows by %d columns into data.\n', size(data, 1), size(data, 2));
Read 17 rows by 4 columns into data.
%====================================================================================
% Sort by column 1.
fprintf('Sorting data by column 1.\n');
Sorting data by column 1.
[sortedData, sortOrder] = sortrows(data, 1);
%====================================================================================
% Sort original cell array also.
fprintf('Sorting original cell array in the same order of rows.\n');
Sorting original cell array in the same order of rows.
ca = ca(sortOrder, :)
ca = 17×5 cell array
{["61728b3e4e680d6c607f514c"]} {[ 8]} {[18]} {[14]} {[22]} {["5d4a41890e604c00011ade8b"]} {[ 9]} {[14]} {[14]} {[15]} {["5dc4bc30569be3387eb6b52f"]} {[10]} {[18]} {[17]} {[25]} {["5f5e7de4c81d3672642cd612"]} {[10]} {[25]} {[15]} {[21]} {["6134c80f7eab0971588b3d3a"]} {[11]} {[13]} {[14]} {[10]} {["5fb6ed2116919c000a99249e"]} {[13]} {[23]} {[16]} {[19]} {["5b59a51fca6d01000157a8c3"]} {[14]} {[ 2]} {[17]} {[11]} {["611b1d3794ac948af7e57e7a"]} {[15]} {[18]} {[17]} {[10]} {["5fd7782dee03dc08d3f3f491"]} {[15]} {[18]} {[16]} {[ 1]} {["5ecbb2347a5125043b1d3588"]} {[15]} {[26]} {[17]} {[13]} {["6155c449ebffeae654abd854"]} {[16]} {[22]} {[ 9]} {[ 5]} {["5eac84ff4efbe80ffd3962f1"]} {[16]} {[13]} {[18]} {[ 6]} {["5f5503435d41a489068ff50b"]} {[17]} {[19]} {[15]} {[11]} {["61520b079436973e05f72d33"]} {[18]} {[12]} {[14]} {[16]} {["5e92f01a49a5ba62bd0d5693"]} {[18]} {[15]} {[14]} {[ 7]} {["607ed750ad800928b1861317"]} {[19]} {[18]} {[14]} {[15]}
Or did you really mean by the long alphanumeric hexadecimal strings in the first column? Like this:
%====================================================================================
storedStructure = struct with fields:
high_empathy_ID_factors: {17×5 cell}
ca = storedStructure.high_empathy_ID_factors;
data = cell2mat(ca(:, 2:end))
data = 17×4
18 12 14 16 17 19 15 11 8 18 14 22 25 11 17 7 16 22 9 5 11 13 14 10 13 23 16 19 10 18 17 25 9 14 14 15 15 18 17 10
[rows, columns] = size(data);
fprintf('Read %d rows by %d columns into data.\n', rows, columns);
Read 17 rows by 4 columns into data.
%====================================================================================
% Convert hex numbers in column 1 to decimal
for row = 1 : rows
c = char(ca{row, 1});
% Can only convert the first 16 digits.
numbers(row) = hex2dec(c(1:16));
end
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
%====================================================================================
% Sort by column 1.
fprintf('Sorting data by column 1.\n');
Sorting data by column 1.
[sortedData, sortOrder] = sort(numbers)
sortedData = 1×17
1.0e+18 * 6.5825 6.7223 6.7567 6.8148 6.8220 6.8307 6.8694 6.8721 6.8970 6.9061 6.9532 6.9972 7.0044 7.0118 7.0127 7.0137 7.0218
sortOrder = 1×17
12 9 8 14 13 16 2 15 7 11 17 10 6 4 1 5 3
%====================================================================================
% Sort original cell array also.
fprintf('Sorting original cell array in the same order of rows.\n');
Sorting original cell array in the same order of rows.
ca = ca(sortOrder, :)
ca = 17×5 cell array
{["5b59a51fca6d01000157a8c3"]} {[14]} {[ 2]} {[17]} {[11]} {["5d4a41890e604c00011ade8b"]} {[ 9]} {[14]} {[14]} {[15]} {["5dc4bc30569be3387eb6b52f"]} {[10]} {[18]} {[17]} {[25]} {["5e92f01a49a5ba62bd0d5693"]} {[18]} {[15]} {[14]} {[ 7]} {["5eac84ff4efbe80ffd3962f1"]} {[16]} {[13]} {[18]} {[ 6]} {["5ecbb2347a5125043b1d3588"]} {[15]} {[26]} {[17]} {[13]} {["5f5503435d41a489068ff50b"]} {[17]} {[19]} {[15]} {[11]} {["5f5e7de4c81d3672642cd612"]} {[10]} {[25]} {[15]} {[21]} {["5fb6ed2116919c000a99249e"]} {[13]} {[23]} {[16]} {[19]} {["5fd7782dee03dc08d3f3f491"]} {[15]} {[18]} {[16]} {[ 1]} {["607ed750ad800928b1861317"]} {[19]} {[18]} {[14]} {[15]} {["611b1d3794ac948af7e57e7a"]} {[15]} {[18]} {[17]} {[10]} {["6134c80f7eab0971588b3d3a"]} {[11]} {[13]} {[14]} {[10]} {["614ec4f7be36eb900905644c"]} {[25]} {[11]} {[17]} {[ 7]} {["61520b079436973e05f72d33"]} {[18]} {[12]} {[14]} {[16]} {["6155c449ebffeae654abd854"]} {[16]} {[22]} {[ 9]} {[ 5]}
##### 3 CommentsShow 1 older commentHide 1 older comment
Image Analyst on 28 Jul 2022
Edited: Image Analyst on 28 Jul 2022
Or maybe read them into tables with readtable(), and use one of the members of the "join" functions to combine the tables.
lil brain on 28 Jul 2022
The join() function actually worked really well. So I used that as it was the simplest approach thanks!