MATLAB Central Newsreader - Get the first element out of each cell of a cell array

Get the first element out of each cell of a cell array

David Doria — Tue, 11 Mar 2008 20:56:02 -0400

I have a cell 4x20 cell array called L

each element of L is a 1x20 vector

How do I make a vector of all the first elements of L(1,:)?

I tried L(1,:)(1) to no avail.

Please let me know,

Thanks!

David

Re: Get the first element out of each cell of a cell array

roberson@ibd.nrc-cnrc.gc.ca (Walter Roberson) — Tue, 11 Mar 2008 21:24:35 -0400

In article <fr6rl1$ifj$1@fred.mathworks.com>,
David Doria <daviddoria@gmail.com> wrote:
>I have a cell 4x20 cell array called L

>each element of L is a 1x20 vector

>How do I make a vector of all the first elements of L(1,:)?
>
>I tried L(1,:)(1) to no avail.

cellfun(@(v) v(1), L(1,:))
--
  "MAMA: Oh--So now it's life. Money is life. Once upon a time freedom
   used to be life--now it's money. I guess the world really do change.
   WALTER: No--it was always money, Mama. We just didn't know about it."
                                              -- Lorraine Hansberry

Re: Get the first element out of each cell of a cell array

us — Wed, 12 Mar 2008 05:34:01 -0400

"David Doria":
<SNIP first in line only...

> I have a cell 4x20 cell array called L
> each element of L is a 1x20 vector
> How do I make a vector of all the first elements of L
(1,:)?
> I tried L(1,:)(1) to no avail...

one of the many solutions

% the data
     c=cell(2,3); % <- your 4x20 cell array
     [c{:}]=deal(1:3); % <- each element being a vec
% the engine
     ca=cat(1,c{:});
     r=ca(:,1);
% the result (as expected)
     disp(c);
     disp(r.');
% 1 1 1 1 1 1

us

Re: Get the first element out of each cell of a cell array

Loren Shure — Thu, 13 Mar 2008 12:41:58 -0400

In article <fr7q09$1vn$1@fred.mathworks.com>, us@neurol.unizh.ch says...
> "David Doria":
> <SNIP first in line only...
>
> > I have a cell 4x20 cell array called L
> > each element of L is a 1x20 vector
> > How do I make a vector of all the first elements of L
> (1,:)?
> > I tried L(1,:)(1) to no avail...
>
> one of the many solutions
>
> % the data
> c=cell(2,3); % <- your 4x20 cell array
> [c{:}]=deal(1:3); % <- each element being a vec
> % the engine
> ca=cat(1,c{:});
> r=ca(:,1);
> % the result (as expected)
> disp(c);
> disp(r.');
> % 1 1 1 1 1 1
>
> us
>
>
caveat that all cells need to have same number of elements for this
solution, I think.

the cellfun solution listed earlier works even if that's not the case.

--
Loren
http://blogs.mathworks.com/loren/