Access value in cell arrays
2 Ansichten (letzte 30 Tage)
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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
2 Kommentare
per isakson
am 29 Jun. 2013
Is A supposed to be a cell arrays of structures?
A field named "str" holding a numerical value isn't that confusing?
Akzeptierte Antwort
per isakson
am 29 Jun. 2013
Bearbeitet: per isakson
am 29 Jun. 2013
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
4 Kommentare
Matt J
am 29 Jun. 2013
You can Accept-click per's Answer, then, since that was what you were looking for.
Weitere Antworten (2)
Matt J
am 29 Jun. 2013
Bearbeitet: Matt J
am 29 Jun. 2013
No. You can do this instead
A(1).str = 1;
A(2).str = 2;
...
A(10).str = 10;
B=[A(:).str]
3 Kommentare
Matt J
am 29 Jun. 2013
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
am 29 Jun. 2013
Bearbeitet: per isakson
am 29 Jun. 2013
I agree.
However, for some reason the cell array may contain structures with only some fields in common.
James Tursa
am 29 Jun. 2013
Another variation:
x = [A{:,1}];
B = [x.str];
2 Kommentare
Matt J
am 30 Jun. 2013
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.
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