python dict sub list append

Asked May 02 '17 at 12:42

Active May 02 '17 at 12:42

Viewed 20 times

I have a dict:

D = {'KEY-2': ['KEY-3.1', 'KEY-3.2']}

I want to change it:

D['KEY-2'] = dict.fromkeys(D.pop('KEY-2'),[])
>>> D
{'KEY-2': {'KEY-3.1': [], 'KEY-3.2': []}}

And append line to one of key subdict

D['KEY-2']['KEY-3.1'].append('line')

And I get:

>>> D
{'KEY-2': {'KEY-3.1': ['line'], 'KEY-3.2': ['line']}}

Why? What can I add line to only list D['KEY-2']['KEY-3.2']?

asked May 02 '17 at 12:42

1

`dict.fromkeys()` does not make copies. – Martijn Pieters May 02 '17 at 12:43
1

Use `D['KEY-2'] = {k: [] for k in D.pop('KEY-2')}`. – Martijn Pieters May 02 '17 at 12:45
This might be a better dupe: http://stackoverflow.com/questions/8174723/dictionary-creation-with-fromkeys-and-mutable-objects-a-surprise – Chris_Rands May 02 '17 at 12:47

0 Answers0