Customizable Natural-Order Sort

Alphanumeric sort of a cell/string/categorical array, with customizable number format.

To sort any file-names or folder-names use NATSORTFILES:

http://www.mathworks.com/matlabcentral/fileexchange/47434-natural-order-filename-sort

To sort the rows of a string/cell array use NATSORTROWS:

http://www.mathworks.com/matlabcentral/fileexchange/47433-natural-order-row-sort

Summary

Alphanumeric sort the text in a string/cell/categorical array. Sorts the text by character code taking into account the values of any number substrings. Compare for example:

X = {'a2', 'a10', 'a1'}; 
sort(X) 
ans = 'a1' 'a10' 'a2' 
natsort(X) 
ans = 'a1' 'a2' 'a10'

By default NATSORT interprets all consecutive digits as integer numbers, the number substring recognition can be specified using a regular expression, allowing the number substrings to have:

• a +/- sign
• a decimal point and decimal fraction
• E-notation exponent
• decimal, octal, hexadecimal or binary notation
• Inf or NaN values
• criteria supported by regular expressions: lookarounds, quantifiers, etc.

And of course the sorting itself can also be controlled:

• ascending/descending sort direction
• character case sensitivity/insensitivity
• relative order of numbers vs. characters
• relative order of numbers vs NaNs

Examples

%% Multiple integers (e.g. release version numbers):
>> A = {'v10.6', 'v9.10', 'v9.5', 'v10.10', 'v9.10.20', 'v9.10.8'};
>> sort(A) % for comparison.
ans =   'v10.10'  'v10.6'  'v9.10'  'v9.10.20'  'v9.10.8'  'v9.5'
>> natsort(A)
ans =   'v9.5'  'v9.10'  'v9.10.8'  'v9.10.20'  'v10.6'  'v10.10'

%% Integer, decimal, NaN, or Inf numbers, possibly with +/- signs:
>> B = {'test+NaN', 'test11.5', 'test-1.4', 'test', 'test-Inf', 'test+0.3'};
>> sort(B) % for comparison.
ans =   'test' 'test+0.3' 'test+NaN' 'test-1.4' 'test-Inf' 'test11.5'
>> natsort(B, '[-+]?(NaN|Inf|\d+\.?\d*)')
ans =   'test' 'test-Inf' 'test-1.4' 'test+0.3' 'test11.5' 'test+NaN'

%% Integer or decimal numbers, possibly with an exponent:
>> C = {'0.56e007', '', '43E-2', '10000', '9.8'};
>> sort(C) % for comparison.
ans =   ''  '0.56e007'  '10000'  '43E-2'  '9.8'
>> natsort(C, '\d+\.?\d*(E[-+]?\d+)?')
ans =   ''  '43E-2'  '9.8'  '10000'  '0.56e007'

%% Hexadecimal numbers (with '0X' prefix):
>> D = {'a0X7C4z', 'a0X5z', 'a0X18z', 'a0XFz'};
>> sort(D) % for comparison.
ans =   'a0X18z'  'a0X5z'  'a0X7C4z'  'a0XFz'
>> natsort(D, '0X[0-9A-F]+', '%i')
ans =   'a0X5z'  'a0XFz'  'a0X18z'  'a0X7C4z'

%% Binary numbers:
>> E = {'a11111000100z', 'a101z', 'a000000000011000z', 'a1111z'};
>> sort(E) % for comparison.
ans =   'a000000000011000z'  'a101z'  'a11111000100z'  'a1111z'
>> natsort(E, '[01]+', '%b')
ans =   'a101z'  'a1111z'  'a000000000011000z'  'a11111000100z'

%% Case sensitivity:
>> F = {'a2', 'A20', 'A1', 'a10', 'A2', 'a1'};
>> natsort(F, [], 'ignorecase') % default
ans =   'A1'  'a1'  'a2'  'A2'  'a10'  'A20'
>> natsort(F, [], 'matchcase')
ans =   'A1'  'A2'  'A20'  'a1'  'a2'  'a10'

%% Sort order:
>> G = {'2', 'a', '', '3', 'B', '1'};
>> natsort(G, [], 'ascend') % default
ans =   ''   '1'  '2'  '3'  'a'  'B'
>> natsort(G, [], 'descend')
ans =   'B'  'a'  '3'  '2'  '1'  ''
>> natsort(G, [], 'num<char') % default
ans =   ''   '1'  '2'  '3'  'a'  'B'
>> natsort(G, [], 'char<num')
ans =   ''   'a'  'B'  '1'  '2'  '3'

%% UINT64 numbers (with full precision):
>> natsort({'a18446744073709551615z', 'a18446744073709551614z'}, [], '%lu')
ans =       'a18446744073709551614z'  'a18446744073709551615z'