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Customizable Natural-Order Sort

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Customizable Natural-Order Sort



05 Jan 2012 (Updated )

Natural-order sort of a cell array of strings, with customizable numeric format.

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File Information

To sort filenames or filepaths use NATSORTFILES:
To sort the rows of a cell array of strings use NATSORTROWS:

### Summary ###

Alphanumeric sort of a cell array of strings. Sorts the strings taking into account the values of any numeric substrings occurring within those strings. Compare for example:

A = {'a2', 'a10', 'a1'};
 ans = 'a1' 'a10' 'a2'
 ans = 'a1' 'a2' 'a10'

By default NATSORT simply treats all consecutive digits as integer values, however NATSORT also provides optional user-control over the numeric substring recognition and parsing via a regular expression, allowing the numeric substrings to have:
* a +/- sign
* a decimal point and decimal fraction
* E-notation exponent
* decimal, octal, hexadecimal or binary notation
* prefixes/suffixes/literals which can be ignored
* Inf or NaN value
* any feature supported by regexp, including look-arounds, quantifiers, etc.

The numeric class can be chosen to suit the substrings' numeric data:
* double
* int
* uint

And of course the sorting itself can also be controlled:
* ascending/descending sort direction
* character case sensitivity/insensitivity
* relative order of numeric substrings vs. characters

### Examples ###

The default is for integer numeric substrings, as shown in the example in the introduction.

% Multiple number substrings (e.g. release version numbers):
B = {'v10.6', 'v9.10', 'v9.5', 'v10.10', 'v9.10.20', 'v9.10.8'};
 ans = 'v10.10' 'v10.6' 'v9.10' 'v9.10.20' 'v9.10.8' 'v9.5'
 ans = 'v9.5' 'v9.10' 'v9.10.8' 'v9.10.20' 'v10.6' 'v10.10'

% Integer, decimal or Inf number substrings, possibly with +/- signs:
C = {'test+Inf', 'test11.5', 'test-1.4', 'test', 'test-Inf', 'test+0.3'};
 ans = 'test' 'test+0.3' 'test+Inf' 'test-1.4' 'test-Inf' 'test11.5'
natsort(C, '(-|+)?(Inf|\d+(\.\d+)?)')
 ans = 'test' 'test-Inf' 'test-1.4' 'test+0.3' 'test11.5' 'test+Inf'

% Integer or decimal number substrings, possibly with an exponent:
D = {'0.56e007', '', '4.3E-2', '10000', '9.8'};
 ans = '' '0.56e007' '10000' '4.3E-2' '9.8'
natsort(D, '\d+(\.\d+)?(E(+|-)?\d+)?')
 ans = '' '4.3E-2' '9.8' '10000' '0.56e007'

% Hexadecimal number substrings (possibly with '0X' prefix):
E = {'a0X7C4z', 'a0X5z', 'a0X18z', 'aFz'};
 ans = 'a0X18z' 'a0X5z' 'a0X7C4z' 'aFz'
natsort(E, '(?<=a)(0X)?[0-9A-F]+', '%x')
 ans = 'a0X5z' 'aFz' 'a0X18z' 'a0X7C4z'

% Binary number substrings (possibly with '0B' prefix):
F = {'a11111000100z', 'a0B101z', 'a0B000000000011000z', 'a1111z'};
 ans = 'a0B000000000011000z' 'a0B101z' 'a11111000100z' 'a1111z'
natsort(F, '(0B)?[01]+', '%b')
 ans = 'a0B101z' 'a1111z' 'a0B000000000011000z' 'a11111000100z'

% uint64 number substrings (with full precision!):
natsort({'a18446744073709551615z', 'a18446744073709551614z'}, [], '%lu')
 ans = 'a18446744073709551614z' 'a18446744073709551615z'

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

% Sort direction:
H = {'2', 'a', '3', 'B', '1'};
natsort(H, [], 'ascend') % default
 ans = '1' '2' '3' 'a' 'B'
natsort(H, [], 'descend')
 ans = 'B' 'a' '3' '2' '1'

% Relative sort-order of number substrings compared to characters:
X = num2cell(char(32+randperm(63)));
cell2mat(natsort(X, [], 'asdigit')) % default
 ans = '!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_'
cell2mat(natsort(X, [], 'beforechar'))
 ans = '0123456789!"#$%&'()*+,-./:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_'
cell2mat(natsort(X, [], 'afterchar'))
 ans = '!"#$%&'()*+,-./:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_0123456789'


Asort: A Pedestrian Alphanumeric String Sorter, Sort Nat: Natural Order Sort, Number To Scientific Prefix, Date Vector/Number To Iso 8601 Date String, Iso 8601 Date String To Serial Date Number, Natural Order Row Sort, Natural Order Filename Sort, Number To Words, Number To Myriad, Words To Number, and Scientific Prefix To Number inspired this file.

This file inspired Iso 8601 Date String To Serial Date Number, Date Vector/Number To Iso 8601 Date String, Number To Myriad, Interactive Regular Expression Maker, Numeric To Ordinal String, Number To Words, Words To Number, Number To Scientific Prefix, Scientific Prefix To Number, Natural Order Row Sort, and Natural Order Filename Sort.

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MATLAB release MATLAB 7.11 (R2010b)
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Comments and Ratings (2)
23 Nov 2016 qiap chen

It's good tool

29 Feb 2016 Chang hsiung

14 Feb 2012 1.1

- Add examples showing different numeric tokens.
- Case-insensitive sort is now default.

24 Aug 2012 1.3

- Implement more compact sort algorithm.
- "sscanf" numeric format can be controlled by an optional input argument.
- Provide use examples.
- Output debugging arrays now char+numeric.

28 Apr 2014 1.4

- Now parses hexadecimal and octal substrings.
- int64 and uint64 parsed at full precision.
- Allow <options> in any order.
- For debugging: return indices of character and numeric arrays.

02 Jul 2014 1.5

- Simplify hexadecimal example.
- Correct output summary.

05 Aug 2014 1.6

- Add binary numeric parsing.
- Improve input checking.
- Replace multiple debugging output arrays with one cell array.
- Allow lookarounds in regular expression.

20 Dec 2014 1.7

- Update documentation only, improve examples.

25 Feb 2015 1.8

* Improved binary substring parsing.
* Better examples.

07 Jan 2016 1.9

* Improve binary numeric handling.
* Improve handling of skipped fields.
* Add an example of skipped field usage.

28 Feb 2016 1.10

* Improve input checking.

29 Sep 2016 1.10

* Add HTML documentation.

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