访问包含ngram的计数器的元素

Question

I am taking a string, tokenizing it, and want to look at the most common bigrams, here is what I have got:

import nltk
import collections
from nltk import ngrams

someString="this is some text. this is some more test. this is even more text."
tokens=nltk.word_tokenize(someString)
tokens=[token.lower() for token in tokens if len()>1]

bigram=ngrams(tokens,2)
aCounter=collections.Counter(bigram)

If I:

print(aCounter)

Then it will output the bigrams in sorted order.

for element in aCounter:
     print(element)

Will print the elements, but not with a count, and not in order of the count. I want to do a for loop, where I print out the X most common bigrams in a text.

I am essentially trying to learn both Python and nltk at the same time, so this could be why I am struggling here (I assume this is a trivial thing).

Answer 1

You're probably looking for something that already exists, namely, the most_common method on counters. From the docs:

Return a list of the n most common elements and their counts from the most common to the least. If n is omitted or None , most_common() returns all elements in the counter. Elements with equal counts are ordered arbitrarily:

You can call it and supply a value n in order to get the n most common value-count pairs. For example:

from collections import Counter

# initialize with silly value.
c = Counter('aabbbccccdddeeeeefffffffghhhhiiiiiii')

# Print 4 most common values and their respective count.
for val, count in c.most_common(4):
    print("Value {0} -> Count {1}".format(val, count))

Which prints out:

Value f -> Count 7
Value i -> Count 7
Value e -> Count 5
Value h -> Count 4