Get tuple of values from nested dict-CodePudding

I'm trying to create a python script that goes through a dict with a structure similar to:

structure = {
    'key1' : {'keyA' : 'valueA1', 'keyB' : {'keyC' : 'valueC1', 'keyD, 'valueD1'} },
    'key2' : {'keyA' : 'valueA2', 'keyB' : {'keyC' : 'valueC2', 'keyD, 'valueD2'}},
    'key3' : {'keyA' : 'valueA3', 'keyB' : {'keyC' : 'valueC3', 'keyD, 'valueD3'}}
}

and returns a tuple, lets say, with every 'valueDX' element where X is 1, 2 or 3. I mean, return a tuple like

(valueD1, valueD2, valueD3)

I tried doing

my_list = []
for x in structure.values():
    my_list.append(x['keyB'].values()['keyD'])

But I have the following error:

TypeError: 'dict_keys' object is not subscriptable

CodePudding user response：

   your_list=[]
   for x1 in structure.values():
      try:
         your_list.append(x1['keyB']['keyD'])
      except:
         pass   # it better use try when dealing dict or unknown structure
   return your_list

you don't have use values() methods to get specific value. it for dict values iteration.

CodePudding user response：

can do it in one liner as long as the keys are the same with every dict and always exist:

my_list = [v['keyB']['keyD'] for k,v in structure.items()]

CodePudding user response：

tuple([structure[key]["keyB"]["keyD"] for key in structure.keys()])
# ('valueD1', 'valueD2', 'valueD3')

CodePudding user response：

you can use dict.get()

your_list=[]
for x1 in structure.values():
    your_list.append(x1.get('keyB').get('keyD'))

print(tuple(your_list))

CodePudding user response：

From the doc dict-methods like values, keys return a dictionary-view-objects. This doesn't provide a direct access to its content as for list, tuple, ... but only iterate through it.

d = {1: 'A'}
print(type(d.values()))
#dictionary-view-objects

# casting the view
print(list(d.values())[0])
#A

# direct access to values of the view raise an error 
try:
   d.values()[0]
except TypeError:
   pass # TypeError: 'dict_keys' object is not subscriptable

Here a possible solution

structure = {
    'key1' : {'keyA' : 'valueA1', 'keyB' : {'keyC' : 'valueC1', 'keyD': 'valueD1'} },
    'key2' : {'keyA' : 'valueA2', 'keyB' : {'keyC' : 'valueC2', 'keyD': 'valueD2'}},
    'key3' : {'keyA' : 'valueA3', 'keyB' : {'keyC' : 'valueC3', 'keyD': 'valueD3'}}
}


my_list = []
key_levels = 'keyB', 'keyD'

for key_i in structure:
    d = structure[key_i]
    for key in key_levels:
        d = d[key]
    my_list.append(d)

my_list = tuple(my_list)
print(my_list)