more efficient way to use strtok / selecting parts of a string

iliya ka asked on 28 Jan 2012 at 11:52

Latest activity: Answer by iliya ka on 28 Jan 2012 at 21:51

Accepted Answer from Daniel

Greetings,

I have a huge cell array with time data arranged in the following format :

[one empty cell];
ABC/DEF QTR/3/99 (Thousands);
ABC/DEF QTR/6/99 (Thousands);
ABC/DEF QTR/9/99 (Thousands);
ABC/DEF QTR/12/99 (Thousands);
etc...

I would like to change the format into this :

ABC/DEF;
QTR/3/99;
QTR/6/99;
QTR/9/99;
QTR/12/99;
etc...

I've solved the problem but think it can be done much more efficiently:

[varname,  mthtime2(2:end)] = strtok(mthtime2(2:end));
mthtime2(2:end)= strtok(mthtime2(2:end));% drops the "thousands"                             mthtime2(1)=varname(1);

Suggestions for a faster method would be most appreciated. Thank you for your time!

Iliya

2 comments

Walter Roberson on 28 Jan 2012 at 16:42

Is the mthtime2(1)=varname(1) commented out, or should it be on the next line?

Daniel on 28 Jan 2012 at 17:10

In order to get what iilya wants, mthtime2(1)=varname(1) needs to be uncommented.

Products

2 answers

Daniel answered on 28 Jan 2012 at 15:17

Accepted answer

If the format is as rigid as your example ...

Given a cell array

x = {[]; 'ABC/DEF QTR/3/99 (Thousands)'; 'ABC/DEF QTR/6/99 (Thousands)'; 'ABC/DEF QTR/9/99 (Thousands)'; 'ABC/DEF QTR/12/99 (Thousands)'};

Then for each element

y = x{i};

you want

y(9:17);

and then need to deal with the possible blank space. The function deblank can handle this. Putting it all together ...

x = {[]; 'ABC/DEF QTR/3/99 (Thousands)'; 'ABC/DEF QTR/6/99 (Thousands)'; 'ABC/DEF QTR/9/99 (Thousands)'; 'ABC/DEF QTR/12/99 (Thousands)'};

[{'ABC/DEF'};cellfun(@(y)(deblank(y(9:17))), x(2:end), 'UniformOutput', false)]

edit to handle variable ABC/DEF

firstCell = x{2};
[{firstCell(1:7)};cellfun(@(y)(deblank(y(9:17))), x(2:end), 'UniformOutput', false)]

0 comments

iliya ka answered on 28 Jan 2012 at 21:51

Thank you very much daniel! It's close to being ok, but the 'ABC/DEF' changes from on variable to another (but kept in the same format) therefore it has to be read from the file.

any more suggestions ?

Iliya

1 comment

Daniel on 28 Jan 2012 at 22:11

This should be a comment on my answer and not a new answer. It makes following threads easier. See my edit to my answer.