What do I have to do to sort strings properly in Listbox?

Hi,

While I try to figure this out, I have problems again..

To sort strings in listbox,

e.g.,I have strings below! 'p1' 'p2' 'p10' 'p12' 'p21'

To sort those strings, I tried to use sort(),

and then, result was like this..

'p1' 'p10' 'p12' 'p2' 'p21'

%%%% :-( %%%%

But, I want to sort A as, 'p1' 'p2' 'p10' 'p12' 'p21'

What do I have to do for this?

I'm looking forward to your answer!

[Geoff]

Hey Haksun Lee... I answered your question with code, and then you deleted the question. If you think I'll answer it again, you're mistaken.

[Walter Roberson]

Geoff, if you answered the copy of the question that was posted about half an hour ago, then I'm the one who deleted that question. There were no responses at the time I looked, but it could be that an answer of yours came in between the time I loaded the question and the time I hit the delete.

[Haksun Lee]

what was happened?-0-

Because there were no answers since I asked about sorting, so I re-ask same question today.

Maybe Geoff answered it, BUT I couldn't check your answers...sorry

[Geoff]

Oh... probably... Meh, well, I'll stop being a grump and hack it out quickly again.

[Haksun Lee]

There was some misunderstanding..

Have a nice day everyone..

But I have to figure this out T.T

- Newbie programmer, H.S Lee

Answer 1

[Geoff]

Don't ask the same question just because nobody answered it yesterday. If you are impatient, write a comment on it to bump it back up. People occasionally check through old questions to see what hasn't been answered. That's also a reason to accept answers - so people who do look back on old questions know not to check those that are already accepted.

Now... code, with no explanation this time.

A = {'p1', 'p10', 'p12', 'p2', 'p21'};
N = cellfun( @str2double, regexp(A, '\d+', 'match') )
[~,I] = sort(N);
B = A(I);

[Haksun Lee]

Thank you Geoff

I've learned lots of things this time!

I will keep them in my mind.

Thank you so much again.

[Walter Roberson]

This can be made shorter:

N = str2double( regexp(A, '\d+', 'match') );

That is, str2double() is able to work on cell arrays of strings, and returns a numeric matrix when it does so.

[Geoff]

@Walter : try it... N = [NaN, NaN, NaN, NaN, NaN]

[Soroush Asarzadeh]

Hello Geoff, I have a similar question, but in my case: A = {'p10=34', 'p4=10', 'p2=11', 'p3=90', 'p21=55'}; so the next line N = cellfun( @str2double, regexp(A, '\d+', 'match') ) causes an error because of the '=' between figures. Do you know how can i fix it? Thanks

[Walter Roberson]

The problem is not the "=" in itself, the problem is that you have not defined which sequence of digits you want to extract out of the two that occur in each string. If you want to extract the first set, then use

N = cellfun( @str2double, regexp(A, '\d+', 'match', 'once') );

[Stephen23]

@Soroush Asarzadeh: This is trivial using my FEX submission natsort:

>> A = {'p10=34', 'p4=10', 'p2=11', 'p3=90', 'p21=55'};
>> natsort(A)
ans = 
    'p2=11'    'p3=90'    'p4=10'    'p10=34'    'p21=55'

PS: hopefully these strings are not going to get evaluated!

[Soroush Asarzadeh]

@Walter thanks, it works now! @Stephan thank u for your answer

[Stephen23]

Note that Walter Roberson's approach from 25 Jun 2012 can be made to work with the addition of the 'once' option (and this is indeed more efficient than calling STR2DOUBLE inside CELLFUN):

A = {'p10=34', 'p4=10', 'p2=11', 'p3=90', 'p21=55'};
N = str2double(regexp(A, '\d+', 'match', 'once'))

N = 1x5

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