Testing for the presence of a substring in a cell array of strings

*NEWBIE WARNING***

I have a very basic question but couldn't find an answer after searching.

I wish to test if a multi-element cell array of strings contains a substring anywhere within the cell array's text, returning a logical true or false answer. For example, given the cell array of strings x:

    x = {'qwer','asdf','zxcv'};

I wish to test if the substring 'xc' is present somewhere in x's text (true in this example).

The method I came up with is as follows:

First, concatenate the elements of the cell array of strings into a single character string, preserving the original character order:

    y = char(x);
    y = y';
    y = y(:)'; % y now equals 'qwerasdfzxcv'

Then, test for the presence of the substring in the concatenated string:

    ~isempty(strfind(y,'xc')) % ans = true
    ~isempty(strfind(y,'123')) % ans = false

Is there a better way to do this that involves less array manipulation? Thank you for your assistance.

Answer 1

[Sean de Wolski]

matches = strfind(x,'xc');
tf = any(vertcat(matches{:}))

[Matt Fig]

This can error if there is a different number of matches per string. For example:

x = {'qwerxc','xcaxcsdf','zxcvxcllxc'};

One could simply switch to using HORZCAT.

I would use:

tf = any(~cellfun('isempty',strfind(x,'xc')))

[Schuyler]

Thank you for this clarification and for the suggestion to use HORZCAT.

Answer 2

[per isakson]

Here is a construct without implicit casting of types

    is_xc = not( cellfun( @isempty, strfind( x, 'xc' ) ) );

and next

    any( is_xc )

Easier to read

    is_xc = cellfun( @has_value, strfind( x, 'xc' ) ) );

where

    function has = has_value( input )
        has = not( isempty( input ) );
    end

Answer 3

[Azzi Abdelmalek]

x = {'qwer','asdf','zxcv'};
out=any(cell2mat(cellfun(@(y) regexp(y,'xc'),x,'un',0)))

or

 out=any(cell2mat(regexp(x,'xc')))

Answer 4

[Demetrio Rodriguez Tereshkin]

OP has already given, in my opinion, the best answer. Although it has to be corrected: isempty() always returns 1 for the type "cell", therefore we should use

cellfun(@isempty,strfind(y,'123'))

Answer 5

[Schuyler]

Wow, all three methods are great! I find:

    matches = strfind(x,'xc');
    tf = any(horzcat(matches{:}))

to be the simplest to visualize because it doesn't involve regular expressions or functions, but they are clearly all effective techniques. Thank you very much for the quick and helpful responses.

[Leo Simon]

This code extends AA's answer to when you need to check if a substring of a string is contained in a cell array:

needLatexForThese = {'\bar','\ubar','\check','\hat'};
stringYes		= '$\bar{x}$'
stringNo		= '$x^\ast$'

f	= @(s) any(cell2mat(cellfun(@(y) contains(s,y),needTexForThese,'un',0)));
f(stringYes)%returns 1
f(stringNo)%returns 0