find a string element in a structure matrix

assume i have a matrix t =

    'abc'
    'defg'
    'hi'
i want to check if 'abc' is in the matrix t

however this code doesnt seem to work

if (find(t == 'abc') >0)

i get the following error message Undefined function or method 'eq' for input arguments of type 'cell'.

[Jan]

FIND replies a vector of indices. Therefore "find()>0" is not working.

Answer 1

[Jan]

The shown data cannot be a matrix, because a matrix must have a rectangular shape. I assume you mean a cell string:

C = {'abc', 'defg', 'hi'};

Then:

if any(strcmp(C, 'abc'))
  disp('abc found');
end

[eliza]

thank you!

Answer 2

[sworland]

I realize that the answer for this was accepted, but the question did say in a "structure matrix", which I interpreted to mean a structure array. For that the following will find the index of the first occurrence,

index = find(strcmp({structname.field}, 'string')==1)

[vettel liu]

Very helpful! Thank you so much.

[Adam Thodey]

Fantastic. just what i was looking for!

[Alex Lord]

Fantastic! Was searching for ages

[Shaul Shvimmer]

Thanks

[gao yang]

Merci!!!!

[dan]

Perfect! Thanks.

Answer 3

[Geoff]

Direct comparison operators (==, etc) don't work with strings.

You need to use strcmp or strcmpi (which ignores case).

Because that function doesn't work on an array, you need to map it:

isabc = cellfun( @(x) strcmp(x,'abc'), t );

This will give you an array of booleans. If you don't care what index the 'abc' occurred at, but just that it exists, you then do this:

if any(isabc)
  % etc
end

To obtain the index of the first occurrence, use this:

firstabc = find( isabc, 1 );

-g-

[Jan]

The == operator does work with strings, try:

a = 'abc', b = '12c', a==b, a=='b';

The only limitation is that both arguments must have the same size or one must be a scalar.

STRCMPI does accept cell strings as inputs such that the CELLFUN approach is not needed.

[eliza]

thank you!