Python Ordered Dictionary
from collections import OrderedDict
# Remembers the order the keys are added!
x = OrderedDict(a=1, b=2, c=3)Python Ordered Dictionary
from collections import OrderedDict
# Remembers the order the keys are added!
x = OrderedDict(a=1, b=2, c=3)python ordereddict
>>> # regular unsorted dictionary
>>> d = {'banana': 3, 'apple': 4, 'pear': 1, 'orange': 2}
>>> # dictionary sorted by key
>>> OrderedDict(sorted(d.items(), key=lambda t: t[0]))
OrderedDict([('apple', 4), ('banana', 3), ('orange', 2), ('pear', 1)])
>>> # dictionary sorted by value
>>> OrderedDict(sorted(d.items(), key=lambda t: t[1]))
OrderedDict([('pear', 1), ('orange', 2), ('banana', 3), ('apple', 4)])
>>> # dictionary sorted by length of the key string
>>> OrderedDict(sorted(d.items(), key=lambda t: len(t[0])))
OrderedDict([('pear', 1), ('apple', 4), ('orange', 2), ('banana', 3)])python counter
>>> # Tally occurrences of words in a list
>>> cnt = Counter()
>>> for word in ['red', 'blue', 'red', 'green', 'blue', 'blue']:
... cnt[word] += 1
>>> cnt
Counter({'blue': 3, 'red': 2, 'green': 1})
>>> # Find the ten most common words in Hamlet
>>> import re
>>> words = re.findall(r'\w+', open('hamlet.txt').read().lower())
>>> Counter(words).most_common(10)
[('the', 1143), ('and', 966), ('to', 762), ('of', 669), ('i', 631),
('you', 554), ('a', 546), ('my', 514), ('hamlet', 471), ('in', 451)]python collections
# Dictionary where key values default to a list:
a = collections.defaultdict(list)
# Dictionary where key values default to 0:
a = collections.defaultdict(int)
# Dictionary where key values default to another dictionary:
a = collections.defaultdict(dict)
'''
Example:
In a regular dictionary, if you did the following:
a = {}
if a['apple'] == 1:
return True
else:
return False
You'd get an error, because 'apple' does not exist in dictionary.
However, if you use collections:
a = collections.defaultdict(int)
if a['apple'] == 1:
return True
else:
return False
This would not give an error, and False would be returned.
Also, the dictionary would now have the key 'apple' with a
default integer value of 0 inside it.
If you used say, collections.defaultdict(list), the default value
would be an empty list instead of 0.
'''python counter
>>> Counter('abracadabra').most_common(3)
[('a', 5), ('r', 2), ('b', 2)]python collections
list = [1,2,3,4,1,2,6,7,3,8,1]
Counter(list)Copyright © 2021 Codeinu
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