Python find maximum string length in the list of lists of lists

big_list = [[['asdf','ad'],['aqwe','rt']],['lkjyui','op'],['dfgh','hjk']]

Goal is to find the maximum string length in the whole big_list

My approach:

big_list = [[['asdf','ad'],['aqwe','rt']],['lkjyui','op'],['dfgh','hjk']]

listdf= pd.concat(pd.DataFrame(item).T for item in big_list ).reset_index(drop=True)
listdf = 
       0     1
0    asdf  aqwe
1      ad      
2  lkjyui    op
3    dfgh   hjk

print(listdf.astype(str).applymap(lambda x: len(x)).max().max())
6

Is there a better way of doing it?

>Solution :

With pandas:

out = listdf.stack().str.len().max()

In pure python:

out = max(len(x) for l in big_list for x in l)

Output: 6