I want to know if there is a way to count element frequencies in a 2D python list. For 1D lists, we can use
list.count(word)
but what if I have a list:
a = [ ['hello', 'friends', 'its', 'mrpycharm'],
['mrpycharm', 'it', 'is'],
['its', 'mrpycharm'] ]
can i find the frequency for each word in this 2D list?
Assuming I understand what you want,
>>> collections.Counter([x for sublist in a for x in sublist])
Counter({'mrpycharm': 3, 'its': 2, 'friends': 1, 'is': 1, 'it': 1, 'hello': 1})
Or,
>>> c = collections.Counter()
>>> for sublist in a:
... c.update(sublist)
...
>>> c
Counter({'mrpycharm': 3, 'its': 2, 'friends': 1, 'is': 1, 'it': 1, 'hello': 1})
Counter(x for sublist in a for x in sublist)You can use a defaultdict:
from collections import defaultdict
d = defaultdict(int)
for sublist in a:
for word in sublist:
d[word] += 1
You already know about list.count(). Simply get the count of word in each sublist and sum them. For example:
>>> my_word = 'its'
>>> sum(sublist.count(my_word) for sublist in a)
2
In case you want the frequency of every word present in your list, there are many good answers available here for that. Alternatively, in case you want to do it without any import (using normal dict), you may do:
my_dict = {}
for sublist in a:
for item in sublist:
if item not in my_dict:
my_dict[item] = 0
my_dict[item] += 1
# Value of my_dict:
{'friends': 1, 'is': 1, 'it': 1, 'its': 2, 'mrpycharm': 3, 'hello': 1}