collections

deque, ordered_dict, defaultdict, counter

from collections import deque
 
deque_list = deque()
for i in range(5):
    deque_list.append(i)
deque_list.appendleft(10)
 
 
from collections import OrderedDict
 
d = OrderedDict()
d['x'] = 100
d['y'] = 200
d['z'] = 300
d['l'] = 500
 
for k, v in d.items():
    print(k, v)
 
from collections import defaultdict
d = defaultdict(object)
d = defaultdict(lambda:0)
print(d["first"])
 
text = "best in the world".split()
print(text)
 
word_count = defaultdict(object)
word_count = defaultdict(lambda:0)
for word in text:
    word_count[word] +=1
 
for i, v in OrderedDict(sorted(word_count.items(), key=lambda t:t[1], reverse=True)).items():
    print(i, v)
 
 
from collections import Counter
 
c = Counter()
c = Counter('gallahad')
print(c)
 

ref : python for machine learning