Access value in cell arrays

조회 수: 2 (최근 30일)
TN
TN 2013년 6월 29일
A{1,1}.str = 1;
A{2,1}.str = 2;
... (so on)
A{10,1}.str = 10;
Can I say:
B = A{:,1}.str;
so that:
B=[1 2 3 4 5 6 7 8 9 10];
Thanks very much
  댓글 수: 2
per isakson
per isakson 2013년 6월 29일
Is A supposed to be a cell arrays of structures?
A field named "str" holding a numerical value isn't that confusing?
TN
TN 2013년 6월 29일
Yes... A is a cell arrays. Each cell array is a structure.
'str' is just a name. It does not mean to be a string. Sorry for the confusion.

댓글을 달려면 로그인하십시오.

채택된 답변

per isakson
per isakson 2013년 6월 29일
편집: per isakson 2013년 6월 29일
What you look for can be achieved with cellfun, see below.
Indexing like C{:}.field is not supported (AFAIK).
The script
S1.field=1;
S2.field=2;
S3.field=3;
C = { S1, S2, S3 };
C{1}.field
C{2}.field
C{3}.field
C{:}.field
returns
ans =
1
ans =
2
ans =
3
Bad cell reference operation.
And
vec = cellfun( @(S) S.field, C, 'uni', true )
returns
ans =
1 2 3
.
EDIT
The single command with cellfun is justified in case the cells of the cell array contain structures with only some fields in common.
Example:
S1.field=1;
S2.field=2;
S3.field=3;
S1.field1=1;
S2.field2=2;
S3.field3=3;
C = { S1, S2, S3 };
vec = cellfun( @(S) S.field, C, 'uni', true )
returns
vec =
1 2 3
  댓글 수: 4
TN
TN 2013년 6월 29일
Thanks very much, Per and Matt. That's it. Sorry... somehow i didn't see the few last lines from "Per". You are all genious!
Matt J
Matt J 2013년 6월 29일
You can Accept-click per's Answer, then, since that was what you were looking for.

댓글을 달려면 로그인하십시오.

추가 답변 (2개)

Matt J
Matt J 2013년 6월 29일
편집: Matt J 2013년 6월 29일
No. You can do this instead
A(1).str = 1;
A(2).str = 2;
...
A(10).str = 10;
B=[A(:).str]
  댓글 수: 3
Matt J
Matt J 2013년 6월 29일
It would not make sense to hold structures having the same fields inside cells. It just makes them harder to get to (as you've discovered).
per isakson
per isakson 2013년 6월 29일
편집: per isakson 2013년 6월 29일
I agree.
However, for some reason the cell array may contain structures with only some fields in common.

댓글을 달려면 로그인하십시오.


James Tursa
James Tursa 2013년 6월 29일
Another variation:
x = [A{:,1}];
B = [x.str];
  댓글 수: 2
TN
TN 2013년 6월 29일
Yes... thanks very much, James. Your solution works great for me too!
Matt J
Matt J 2013년 6월 30일
TN, if James solution works for you, there is really no reason to be carrying around A. You may as well just use x. As per said, it might make sense if A{i} were structs with different fields, but James' approach will not work if that is the case.

댓글을 달려면 로그인하십시오.

카테고리

Help CenterFile Exchange에서 Graphics Object Programming에 대해 자세히 알아보기

태그

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by