finding nth elements in multiple arrays

I have multiple cell arrays: [93x2 double] [216x2 double] [128x2 double][121x2 double] [ 90x2 double] ...so on. These correspond to XY plots,

plot(a{i}(:,1),a{i}(:,2))

opens a plot which looks as fig attached. I want to get the Y values at 1/4th, 1/2 and 3/4th of X for all cells. How can I go about doing this?

Thanks

[KSSV]

Why don't you merge all the cells into single matrix and get what you want?

[Walter Roberson]

So for the 93x2 double array, would the "1/4 of X" be at index (round(93/4),2), or would it be a matter of determining where min(X) + (max(X)-min(X))/4 is in the vector and taking the corresponding Y?

If the X coordinates are equally spaced then the two are equivalent; if the X coordinates are not equally spaced then we need to know whether you mean 1/4 by position or 1/4 by range.

[BoIs]

I want separate values for what Im doing. I want those numbers for each of the cells individually.

[BoIs]

Yeah I wanted X by position. Thanks for the answer!

Answer 1

[Walter Roberson]

Presuming Y is in the second column and that you want the 1/4 by position instead of by range:

cellfun( @(C) C(round([end/4, end/2, 3*end/4]), 2), YourCell, 'Uniform', 0)

[BoIs]

That worked! Thank you so much!

Answer 2

[KSSV]

a = {rand(93,2) ;rand(216,2) ; rand(128,2) ; rand(121,2) ; rand(90,2)} ;
data = cell2mat(a) ;
% plot(data(:,1),data(:,2),'r') ;
N = length(data) ;
%%1/4th value 
data(N/4,:)
%%1/2 value 
data(N/2,:) 
%%3/4th value 
data(3*N/4,:)

Note that N should be divisible by 1/4,1/2 and 3/4. In this case it was. If not you should use fix. For Ex. data(fix(N/4),:) etc.