根据元组填充列表中的元素选择某些元组

Question

I am doing some NLP with NLTK and I have a Counter() sequences, for example

x = [(('DT', 'NN'), 59), (('NN', '.'), 50)]

After searching I should end up with a list of all the tuples with the above requirement.

y = [(('DT', 'NN'), 59)]

My question is, how can I efficiently select all the elements that have 'DT' as the first element of the inner tuple without O(n) time, in the most pythony way?

Answer 1

As metatoaster has elaborated in his comment, you would prob. have to restructure your data to perform the operation in the exact way you want (without O(n)).

That being said, in the current state and with reference to your example, you could do:

y = [t for t in x if t[0][0] == 'DT']