Associative Arrays (Hashes) and the Attribute Library

Developers Ruby API
1

Is it okay to store associative arrays within the attribute libraries? I thought I saw somewhere that this is not possible.

I’m already storing text, numbers, points and multi dimensional arrays.

I can test it on this end but I just wanted to check with others if this will cause any known issues or stability problems etc…

2

When I try to store a basic hash I only get nil.

Here is the test hash I’m creating and trying to store:

testhash = Hash.new
testhash[2] = [192.0,5.5]
testhash[5] = [48.0,5.5]
testhash[7] = [144.0,3.5]

groupi.set_attribute 'TRUSS', 'BPHASH', testhash
3

Yet I can store this multi-dimensional mess of an array:

[ [ 2, [192.0, 5.5]], [ 5, [48.0, 7.5]], [ 7,[144.0,3.5]]]

4 
testarray = Array.new
testarray << [2,[192.0,5.5]]
testarray << [5,[48.0,7.5]]
testarray << [7,[144.0,3.5]]

instancei.set_attribute 'TRUSS', 'BPHASH', testarray

testarray2 = instancei.get_attribute 'TRUSS', 'BPHASH'
puts "#{testarray2}, #{testarray2[1][1][1]}"
5

It is strange to me that we cannot store hashes in the attribute library, why is that?

6

You might try using json. I’m pretty sure it can handle Hashes and there should be no issue storing them in attribute dictionaries because json is pure strings.

2 Likes
7

Yep, I second the use of JSON.

groupi.set_attribute( 'TRUSS', 'BPHASH', testhash.to_json )

… and sometime later:

restored_hash = JSON.parse(groupi.get_attribute( 'TRUSS', 'BPHASH' ))
1 Like
8

If the possibility of nested hashes exists now or in the future, then json is probably best.

If not, Hash#to_a and Array#to_h may be helpful.