On 2010-06-07 17:01:42 +0200, Michael Williams said:
> xx = findgen(5)
> y = 1.0
> str1 = {one: xx, two:y}
>
> xx = findgen(3)
> y = -1.0
> str2 = {three: xx, four: y}
>
> I want to merge them into one flat structure of their elements. At the
> moment I am doing this manually:
I now have a related question. If
IDL> x = {a: [1,2], b: [3,4]}
IDL> y = {a: [5,6], b: [7:8]}
then doing
IDL> z = [x, y]
works, but yields, for example,
IDL> print, z.a
1 2
5 6
IDL> help, z.a
<Expression> INT = Array[2, 2]
I would like to concatenate two structures with matching tags by simply
appending arrays, so that I get a structure in which
IDL> print, z.a
1 2 5 6
IDL> help, z.a
<Expression> INT = Array[4]
Is there a built-in way of doing this? The structures I am
concatenating will always be defined such that the individual tags can
be concatenated trivially like
IDL> a = [x.a, y.a]
IDL> print, a
1 2 5 6
but the only way I can think of doing this for the entire structure is
by iterating over the tags and using the execute procedure
[implementation after the signature], which is obviously spectacularly
inelegant. Is there a better way?
-- Mike
[*] Like this. test_append_struct shows it in use.
function append_struct, tx, ty
tags = tag_names(tx)
s = 'tmp = create_struct("' + tags[0] + '", [tx.' + tags[0] + $
', ty.' + tags[0] + '])'
void = execute(s)
for i = 1, n_elements(tags) - 1 do begin
s = 'tmp = create_struct(tmp, "' + tags[i] + '", [tx.' + tags[i] + $
', ty.' + tags[i] + '])'
void = execute(s)
endfor
return, tmp
end
pro test_append_struct
p1 = {x: 0, y:1, z: 1.5}
p2 = {x: -1, y:2, z: 4}
p = append_struct(p1, p2)
help, p, /struct
print, p.x
print, p.y
print, p.z
p = append_struct(p, p2)
help, p, /struct
print, p.x
print, p.y
print, p.z
end
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