deleting words from a cell array

if I have a cell array

x={'areach';'aread';'areal';'areality';'arean';'arear';'areasoner';'areaway';'areca';'arecaceae'}

y='a'

word='areach'

How do I delete all the words from x that do not have y in the positions it appears in word

for example 'a' appears as the 1st and 4th letter of word, delete all words from dictionary that do not have 'a' as their 1st and 4th position letters. so x would become

x={'areach';'aread';'areal';'areality';'arean';'arear';'areasoner';'areaway'}

(it got rid of 'areca' and 'arecaceae)

Answer 1

[Mohammad Abouali]

x={'areach';'aread';'areal'; ...
   'areality';'arean';'arear'; ...
   'areasoner';'areaway';'areca'; ...
   'arecaceae'};

y='a';

word='areach';

% This line does the trick;
x=x(cellfun(@(c) all(c(find(word==y))==y),x))

x = 

      'areach'
      'aread'
      'areal'
      'areality'
      'arean'
      'arear'
      'areasoner'
      'areaway'

Note that the position 1 and 4 are not hard coded. They are defined based on the y and word

[Mohammad Abouali]

you can also use

x=x(cellfun(@(c) all(c(word==y)==y),x))

i.e. without using find().

Answer 2

[bio lim]

x={'areach';'aread';'areal';'areality';'arean';'arear';'areasoner';'areaway';'areca';'arecaceae'};
for n = 1 : length(x)
 if ~strcmp(x{n}(4),'a')
  x{n}=[];
 end
end