SO_36918341

% Generate some dummy data
mystrs = {'hi hello this is robin'; ...
          'we are the knights who say ni'; ...
          'this is a string'; ... 
          'knight rider'; ...
          'boogie nights'; ...
          'boogie knights'; ...
          };
  
querystr = 'knight';
% Generate regular expression...expression based on query string
expression = sprintf('\\<(%s)\\>', querystr);
% Return where matches start in each cell
matchstart = regexp(mystrs, expression, 'start');
% Find first non-empty cell, signifying a match
firstcellwithquerystring = find(~cellfun(@isempty, matchstart), 1, 'first');