sort_nat: Natural Order Sort
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- 226 downloads
Editor's Note: This file was selected as MATLAB Central Pick of the Week
Natural order sorting sorts strings containing digits in a way such that the numerical value of the digits is taken into account. It is especially useful for sorting file names containing index numbers with different numbers of digits. Often, people will use leading zeros to get the right sort order, but with this function you don't have to do that. For example, with input of
{'file1.txt','file2.txt','file10.txt'}
a normal sort will give you
{'file1.txt','file10.txt','file2.txt'}
whereas, sort_nat will give you
{'file1.txt','file2.txt','file10.txt'}
Cite As
Douglas Schwarz (2020). sort_nat: Natural Order Sort (https://www.mathworks.com/matlabcentral/fileexchange/10959-sort_nat-natural-order-sort), MATLAB Central File Exchange. Retrieved .
Comments and Ratings (91)
Updates
| 1.3.0.0 | Fixed bug identified by Evgeny Pr. (Thanks!) |
|
| 1.2.0.0 | Added ability to sort in descending order. |
|
| 1.1.0.0 | Steve Herman identified an obscure bug (sorting a cell array of one string which has no numeric characters) which has now been fixed. Thank you Steve! |
|
| 1.0.0.0 | Fixed ambiguity of sort order in certain cases e.g., {'a0','a00'}. Increased speed. Relaxed MATLAB version requirements -- no longer requires R2006a, should work with much older versions now. |
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Acknowledgements
Inspired: Depth of field calculator based on 2D digital image correlation data, Customizable Natural-Order Sort, philipptempel/matlab-projectmanagement, Natural-Order Row Sort, Natural-Order Filename Sort, Lilo : Fast and pixel-accurate stitching for 2D tiles, KANTOO, DETEQT
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Binyuan Chen (view profile)
s (view profile)
sun wei (view profile)
Thanks very muck !!!!
feng wang (view profile)
非常感谢，看似简单的处理，但是却解决了让人很头疼的问题！！
lidia Talavera (view profile)
Thomas Boomgaard (view profile)
Great submission, and it is a must in many of my scripts. If you happen to need to use this for strings with decimals in them, you can try to replace the regex '\d+' with '\d+(?:\.\d+)?', for example the current version does this:
A = { '1.test', '10.test', '2.test', '1.3.test' }
sort_nat(A)
ans =
1×4 cell array
'1.3.test' '1.test' '2.test' '10.test'
But with the change you get '1.test' '1.3.test' '2.test' '10.test'.
Angkoon Phinyomark (view profile)
Kathy Song (view profile)
^^Thank you soooooo much! It should be a required function for Matlab.
Steve Parker (view profile)
Justin Lee (view profile)
Lilly Aurelius (view profile)
Very useful, thanks!!
circuit_designer5172 (view profile)
This is a fantastic utility. Thanks!
Noushin Hajarolasvadi (view profile)
Oren Shriki (view profile)
Mario Borja-Perez (view profile)
Super handy
Philipe Ambrozio Dias (view profile)
Mauro (view profile)
Thanks Douglas
Douglas Schwarz (view profile)
Antonio, this page is for my submission, sort_nat. natsort and natsortfiles are submissions from another author. Search for them.
Antonio Gutierrez (view profile)
I am working with 2016a Matlab version and I don't find this function: natsort, natsortfiles
Help please!!!!!!!!!
LIU Jordan (view profile)
Luca Daccà (view profile)
Very useful! Thank you!
kes22 (view profile)
Marianna Hovsepyan (view profile)
Philipe Ambrozio Dias (view profile)
Will Turner (view profile)
Thanks!
Zuzana Kvicalova (view profile)
Exactly what I needed, great tool! Thanks a million! :)
Kyle Chadwick (view profile)
exactly what I needed!
Patricia (view profile)
Thank you sooo much :-)
Mortada Haidar (view profile)
Nice and Tidy!
Eli F (view profile)
wei fang (view profile)
a very nice tool, thanks!
eFKa (view profile)
perfect, thanks. Have a nice day :)
Douglas Schwarz (view profile)
eFKa, sort_nat requires a cell array of strings. You can do what you want like this:
[~,order] = sort_nat({files.name});
files_sorted = files(order);
We are using the second output to get the order and then applying that order to your original structure.
Doug
eFKa (view profile)
i have a 50x1 struct called files and a field called name like so
'10up.txt'
'11up.txt'
.
.
.
'19up.txt'
'1up.txt'
how do i use sort_nat(files.name) gives me error saying "too many input arguments"
Demo (view profile)
Sangjae (view profile)
Thanks!!
JWall (view profile)
jenny (view profile)
Deyan Levski (view profile)
Excellent! Works flawlessly, saved some time of an electronic engineer. Thank you!
Karim Barsim (view profile)
JavaDuncan (view profile)
Ulysses C (view profile)
nathan q (view profile)
Stephen Cobeldick (view profile)
Sorting filenames using a sort function such as "sort_nat" can return non-user-intuitive ordering, as some longer filenames will sort before shorter filenames. This is due to char(0:45), including [ !"#$%&'()*+,-], sorting before the period '.' (char(46) used as the extension separator. For example:
fnm = {...
'test2.m';
'test.m';
'test10.m';
'test1.m';
'test-A.m';
'test_A.m';
'test10-old.m'};
% "sort" gives the wrong order for numeric substrings:
sort(fnm)
ans = {...
'test-A.m';
'test.m';
'test1.m';
'test10-old.m';
'test10.m';
'test2.m';
'test_A.m'}
% "sort_nat" gives numeric substrings in the correct order, but with '-' before '.':
sort_nat(fnm)
ans = {...
'test-A.m';
'test.m';
'test1.m';
'test2.m';
'test10-old.m';
'test10.m';
'test_A.m'}
% Note how 'test-A.m' occurs before the shorter named 'test.m', and likewise 'test10-old.m' before 'test10.m'. Users expecting shorter filenames to sort before longer ones need to sort using a different algorithm...
One solution is to sort the filename and file extensions separately, for which I wrote a function "natsortfiles":
natsortfiles(fnm, '\d+', 'beforechar')
ans = {...
'test.m';
'test1.m';
'test2.m';
'test10.m';
'test10-old.m';
'test-A.m';
'test_A.m'}
It allows control over case sensitivity, sort direction, and numeric substring matching. You can find this function on FEX here:
http://www.mathworks.com/matlabcentral/fileexchange/47434
It also accepts fullpaths, for which it sorts each level of the directory hierarchy separately too.
Maryam (view profile)
Thank you very much. It is in the same folder. This is why I am very surprised.
Douglas Schwarz (view profile)
Maryam, make sure that sort_nat.m is in a folder that is on your MATLAB path. You can read more about the path with "doc path".
Maryam (view profile)
Hello. I wan to use this program to sort a vector a strings which have numerical values in their name. I am giving this error: Undefined function 'sort_nat' for input arguments of type 'cell'
what should I do?
Morad Kassem (view profile)
Douglas Schwarz (view profile)
Sergey,
Well, it's not a bug, but you might disagree with my logic. Remember, we are sorting strings, not numbers. '01' comes after '1' because they have the same numerical value, but '01' is a longer string. Likewise, '000' comes after '00', etc.
It may be possible to include '+-.,' by changing the regular expressions (currently just looking for runs of digits with '\d+'.
Serge (view profile)
Very fast! I can't beat it!
This might be a bug though, not sure?
sort_nat({'01E2' '1E3'})
ans = '1E3' '01E2'
I came up with a version that can treat '+-.,' as part of the number, but its 10x slower. Not sure if sort_nat can be extended to do same.
alex (view profile)
thank you very much!
i was typing C=[list.name] and not
C={list.name} which is the right.
thank you very much again!
very usefull function!
Douglas Schwarz (view profile)
Alex, your input has to be a cell array:
>> C = {'1.bmp','10.bmp','11.bmp','2.bmp'};
>> sort_nat(C)
ans =
'1.bmp' '2.bmp' '10.bmp' '11.bmp'
alex (view profile)
alex (view profile)
i find this very useful,but i cant use it.
C =
1.bmp10.bmp11.bmp2.bmp
>> [S,INDEX] = sort_nat(C)
Cell contents reference from a non-cell array object.
Error in sort_nat (line 62)
num_val(i,z(i,:)) = sscanf(sprintf('%s ',digruns{i}{:}),'%f');
any help?
Calum (view profile)
Very useful - worked was described! Thanks.
JiaDa (view profile)
It work well and help a lot. So awesome!!!
Thank you
Dirk (view profile)
Thank you so much, saved me a lot of time! Dirk
Paul (view profile)
Erwin (view profile)
Yi Sui (view profile)
Gregory (view profile)
Peter Beemiller (view profile)
Ekaterina (view profile)
Sorry, I am a beginner in MATLAB and I am not sure what the input arguments in these function mean. There are many input argument.... I have a struct array (conists of files with names ex.123_1, 123_2, etc) A <3000*1> struct and I want to sort it according to name of files which are there. How shoud I use this function... Please help me.. best wiches Katya
salvatore savo (view profile)
thanks a lot!!! great
Harish S (view profile)
Excellent
Nopparat (view profile)
Muhammet (view profile)
Caleb (view profile)
Just what I needed, thanks!
Shamir Alavi (view profile)
I have wasted a lot of time trying to properly sort my image files for my image processing project before I surfed on to this code. And mathworks web tutorial on this is totally flawed. Great work! Certainly deserves a 5 star.
Damon Bradley (view profile)
Excellent work. Saved me a much time and headache with some data analysis over here at NASA. Thank you!
Damon Bradley (view profile)
Ben (view profile)
This is great! Better to include it in the Matlab!
Johanna (view profile)
Jun (view profile)
Many thanks, save me time and effort to write my own code to crack this problem
Carsten (view profile)
Edwin Carter (view profile)
Great, works straight off in Octave too.
Evgeny Pr (view profile)
Douglas Schwarz,
You offered the perfect solution for case-insensitive sorting.
Thank you!
Douglas Schwarz (view profile)
Evgeny, you must be the first person to use descending order and the index. You are quite right, it's a bug and I thank you for identifying it. I fixed it in a slightly different way and just uploaded the new version.
To do case-insensitive sorting you can just do this:
c = {'a1', 'a2', 'a10', 'b1', 'X1', 'A10'};
[unused,index] = sort_nat(lower(c));
cs = c(index);
I want sort_nat to work the same way as sort and since sort doesn't do case-insensitive sorting I left that out of sort_nat as well.
Regards,
Doug
Evgeny Pr (view profile)
This code not entirely correct:
if strcmpi(mode,'ascend')
cs = c(index);
else
cs = c(index(end:-1:1));
end
Output argument INDEX does not change depending on the sort order.
Better to do so:
if strcmpi(mode, 'descend')
index = flipud(index);
end
cs = c(index);
index = reshape(index, size(cs)); % same as C array dimension
Evgeny Pr (view profile)
Hi! Very good function and coding!
I could not write such a elegant and fast function. :)
One question:
You would not want to make sort mode a case-insensitive?
For Example:
c = {'a1', 'a2', 'a10', 'b1', 'X1', 'A10'}
Case-sensetive sort:
cs = {'A10', 'X1', 'a1', 'a2', 'a10', 'b1'}
Case-insensitive sort:
cs = {'a1', 'a2', 'a10', 'A10', 'b1', 'X1'}
Oscar (view profile)
Pete (view profile)
Excellent. 5 stars.
I think I ran into the need for a descending sort because I was looking to search through various files with timestamps in their name for the most recent entry (of something-or-other).
Anyway, good work.
Douglas Schwarz (view profile)
Pete, I'm not sure sorting in descending order will be used very often, but, as you say, it's easy to add so why not? I chose to do it in a slightly different way, but it works the way you want. Thanks for the suggestion. Update should appear soon.
Pete (view profile)
Good work.
Is it just me though or would this not benefit from being able to specify the direction? This would be as simple as:
function [cs,index] = sort_nat(c,varargin)
... <entire code>
if nargin>1
if strcmpi(varargin{1},'descend')
index = flipud(index);
cs = c(index);
end
end
Adam Baker (view profile)
I wish I'd found this sooner!
Nifty, thanks.
Thanks
Nice! Thanks
Great, just what I needed.
Perfect. Should be included in R2007a!
Great, much better than another file on the exchange "sortn", sortn froze when trying to sort over 6000 strings, this sort did it just fine in about a second.