Python extract properties from list of listed objects

Question

I have list of assembly class instances. The total number of assemblies in the list can change.

ASM_list = [ASM1,ASM2,ASM3...etc]

each assembly has a list of parts (I have filtered the assemblies to all have the same parts)

ASM1.parts = ['hood','fender','door']
ASM2.parts = ['hood','fender','door']

each part has properties

ASM1.parts[0].color = green
ASM2.parts[0].color = blue

I would like to print out part properties for each assembly. Example output:

part, ASM1, ASM2, ASM3
hood, green, blue, red
fender, black, red, yellow
door, yellow, green, orange

I'm having trouble using zip or map to do this.

An example of what I'm trying below.

parts_list = []
for ASM in ASM_list:
  parts_list.append([p.color for p in ASM.parts])
print zip(*parts_list)

The "Python cookbook" and several other stack overflow posts show how to iterate through multiple list at the same time, the problem I have is that the number of assemblies changes so I can't write:

for a,b,c in ASM_lists:
  a.part.color, b.part.color, c.part.color

Thanks!

emmagordon · Accepted Answer · 2016-03-24 17:05:34Z

1

Assuming you have a list of part_names - which, if your part objects objects have a name attribute as well as a color attribute, you could get by:

part_names = []
for part in ASM_list[0].parts:
    part_names.append(part.name)

Then you can get the output you want with:

headers = ["part"]
for i, ASM in enumerate(ASM_list):
    headers.append("ASM%d" % (i+1))
print(", ".join(headers))

for i, part_colors in enumerate(zip(*parts_list)):
    part_name = part_names[i]
    print(part_name + ", " + ", ".join(part_colors))

answered Mar 24, 2016 at 17:05

emmagordon

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3 Comments

twinturbotom Over a year ago

I greatly appreciate your insight. I don't fully grasp all of it yet, as of now I'm getting an "expected string, float found" error on the final print statement. I tried str(part_name) to no avail.

twinturbotom Over a year ago

This works... The failures comes from me using this pattern on part properties that are floats (part dimensions). Maybe with some tuple formatting it will be reusable?

twinturbotom Over a year ago

" ".join(map(str, a)) converts to a string for join. THANKS!

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