Question

Python newbie here and wanted to know if there was a way to combine two lists into a dictionary in a way where value can be a specific number. Here’s an example of the 3 datasets I’m trying to combine:

[17, 39, 9]  [13, 37, 13]  =  0.13517353359
[17, 39, 9]  [15, 38, 10]  =  0.055003044449
[13, 39, 13]  [13, 37, 13]  =  0.0345037548204
[13, 39, 13]  [15, 38, 10]  =  0.0801704891415
[14, 39, 12]  [13, 37, 13]  =  0.0596711995129
[14, 39, 12]  [15, 38, 10]  =  0.055003044449
[15, 39, 11]  [13, 37, 13]  =  0.0848386442054
[15, 39, 11]  [15, 38, 10]  =  0.0298355997564
[16, 39, 10]  [13, 37, 13]  = 0.110006088898
[16, 39, 10]  [15, 38, 10]  =  0.0298355997564

I really want to be able to sort the numbers(I have a function that does this working already) and want to lookup by the first list(but need the second list as a reference).

I thought of doing something like name = "%s-%s" % ([16, 39, 10], [15, 38, 10]) then adding name to a dict(with the number being the value) but the problem with this I couldn’t search [16, 39, 10] to get the result. I could make a dict like {[16, 39, 10]:[[15, 38, 10], 0.0298355997564]} but then my search function breaks.

I suspect I might have to do something wonky, but I was wondering if there was a better way to approach this? Ideally I want a simple dict like {[16, 39, 10]:0.0298355997564} and [15, 38, 10] being some kind of attribute that I can reference when needed).

Is this possible?

edit: more details: I need it(reference, second list) there in case I need to reference it later(in this specific example, when I come across a duplicate for [16, 39, 10] I would use the second list to differinate between the results but in my full dataset there aren’t many duplicates so its just to refer to in specific cases).

Answer 1

Lists can’t be dictionary keys, since they are mutable. If the data is static you can convert it to a tuple and use that as a key. The values can also be a tuple of the second list and float value.

   data = {
        (17, 39, 9):  ([13, 37, 13], 0.13517353359),
        (17, 39, 9):  ([15, 38, 10], 0.055003044449),
        (13, 39, 13):  ([13, 37, 13], 0.0345037548204),
   }

   print "Other list:", d[(17, 39, 9)][0]
   print "Float", d[(17, 39, 9)][1]