What would be the most optimised way to access values in a nested array whilst respecting pep8?

I have been using nested arrays parsed from a json. This ends up giving a gigantic line each time I try to access values in the data. let's say I have a nested array in the var data, when I try to reach the deeper values, I still have to respect the 80 characters limit. All I want to do is read or modify the value.

self.data["name1"]["name2"][varWithNumber][varWithNumber2][varWithNumber3]

Now, I thought about two possible solutions I could use:

1- split it using temporary vars and then reasign it to the data once I am done ex:

tempData=self.data["name1"]["name2"][varWithNumber]
tempData[varWithNumber2][varWithNumber3]+=1
self.data["name1"]["name2"][varWithNumber]=tempData

I guess this solution would use quite a bit of ressources from all the memory copied around.

2- use the exec function implemented in python and split the string on multiple lines:

exec ('self.data'+
      '["name1"]'+
      '["name2"]'+
      '[varWithNumber]'+
      '[varWithNumber2]'+
      '[varWithNumber3]+=1')

I have no idea how optimised is the exec function. What would be the most pythonic/optimised way to do this? Is there any other/better way to reach the goal whilst respecting the pep8?

Solution

(Bit long for a comment) You don't need exec to do that... you can use the line continuation operator:

self.data["name1"]\
         ["name2"]\
         [varWithNumber]\
         [varWithNumber2]\ 
         [varWithNumber3]

Demo:

In [635]: x = [[[[1, 2, 3]]]]

In [636]: x[0]\
     ...:  [0]\
     ...:  [0]\
     ...:  [0]
Out[636]: 1

This seems like the easiest and cleanest way to do it.

Don't use exec unless you have to. Actually, don't use it, ever.

In some cases, keeping a reference to a sub dict works if you are to frequently visit that part of your data structure again and again. It is a matter of deciding what is the best solution to apply given the situation and circumstances.