# strfind when I have more than one row

Asked by joseph Frank on 29 Jun 2011
Latest activity Answered by Roland on 29 Dec 2011

K = STRFIND(TEXT,PATTERN)

I am trying to find Pattern in an array of many rows but I am receiving an error : ??? Error using ==> strfind Input strings must have one row

Is there any function taht would substitute strfind in this case?

## 1 Comment

Sean de Wolski on 29 Jun 2011

Does your pattern take up multiple rows?

## Products

No products are associated with this question.

Answer by Matt Fig on 29 Jun 2011

You have a couple of choices with STRFIND. You could loop over the rows, or pad the array with NANs (or other irrelevant value) then reshape to one long string. For example:

```A = [1 2 3 4 5 6;7 6 5 6 3 2;1 2 3 4 5 6]
```
```for ii = 1:size(A,1)
L{ii} = strfind(A(ii,:),[5 6]); % Preall if large A.
end
```
```B = [A nan(size(A,1),1)];
```
```strfind(reshape(B.',1,[]),[5 6])
```

Answer by Paulo Silva on 29 Jun 2011
```a=['Congratulations'
'to Walter      '
'for his 4000   '
'reputation     '
'points         ']
rc=[];
for r=1:size(a,1)
c=strfind(a(r,:),'Walter');
if ~isempty(c)
rc=[rc; r c]; %just in case the word appears multiple times
end
end
rc %first column is the row and second column is the column where the word is
```

## 1 Comment

Roland on 29 Dec 2011

This also does not work well. E.g. if one row has multiple matches this will cause an inconsistent dimensions error.

Answer by Teja Muppirala on 30 Jun 2011

STRFIND works on cells too:

```a=['Congratulations'
'to Walter      '
'for his 4000   '
'reputation     '
'points         '
'WalterWalterWal']
```
```pat = 'Wal'
```
```strfind(cellstr(a),pat)
```

## 1 Comment

Roland on 29 Dec 2011

This does not work well. E.g. if one row has multiple matches this will cause an inconsistent dimensions error.

Answer by Roland on 29 Dec 2011

This is a possible solution ... not perfect though:

```%
% Look for a in b. Returns cell array of
% strfind results for each row.
%
% Usage: strfindmultirow(<searchdata>, <searchpattern>);
%
% e.g. if:
%
% a=['Congratulations'
%    'to Walter      '
%    'for his 4000   '
%    'reputation     '
%    'points         ']
%
% rc = strfindmultirow(a, 'a');
%
% yields:
% rc = strfindmultirow(a, 'a')
% ans = [1x2 double]    [5]     []    [6]     []
%
function rc = strfindmultirow(a, b)
```
```rc={};
for r=1:size(a,1)
c=strfind(a(r,:), b);
rc{length(rc) + 1} = c;
end
```