Multiple variable list comprehension python

Question

I am trying to iterate over multiple object. How can i rewrite it using list comprehension?

for character in characters_rs:
    for item in mapping:
        if character.Get('NomId') == item.get('Номенклатура'):
            item['Attributes'] = character.Get('Attributes')

I tried something like aggregated_list = [character for character in characters_rs for item in mapping if character.Get('NomId') == item.get('Номенклатура') ] , but it's not what i expect.

mapping is a list, characters_rs is a custom RecordSet structure.

You don't seem to be building a list here, so you shouldn't use a list comprehension at all. — user2357112
– user2357112, Commented Oct 29, 2019 at 3:23
You cannot have an assignment statement in a list comprehension. — DYZ
– DYZ, Commented Oct 29, 2019 at 3:26
What type of data are character.Get('NomId') and item.get('Номенклатура') - are they integers, strings, something else? — kaya3
– kaya3, Commented Dec 9, 2019 at 20:43

jferard · Accepted Answer · 2019-12-09 20:39:29Z

You can swap the two loops since they are independent. That makes the process clearer: you want to update some of the items of the mapping iterable:

for item in mapping:
    for character in characters_rs:
        if character.Get('NomId') == item.get('Номенклатура'):
            item['Attributes'] = character.Get('Attributes')

More precisely, you update each item with the last character having character.Get('NomId') == item.get('Номенклатура'). Hence the list/dict comprehension that returns the updated version of mapping:

[{**{'Attributes': character.Get('Attributes')
     for character in characters_rs
     if character.Get('NomId') == item.get('Номенклатура')},
  **item}
 for item in mapping]

Explanation: {**d1, **d2} merges two dicts. Here, the first dict contains the last character having character.Get('NomId') == item.get('Номенклатура') mapped to Attributes (this dict may be empty), and the second is simply item itself.

Collectives™ on Stack Overflow

Multiple variable list comprehension python

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related