Counting Unique Words In Python
Solution 1:
The best way to count objects in Python is to use collections.Counter
class, which was created for that purposes. It acts like a Python dict but is a bit easier in use when counting. You can just pass a list of objects and it counts them for you automatically.
>>> from collections import Counter
>>> c = Counter(['hello', 'hello', 1])
>>> print c
Counter({'hello': 2, 1: 1})
Also Counter has some useful methods like most_common, visit documentation to learn more.
One method of Counter class that can also be very useful is update method. After you've instantiated Counter by passing a list of objects, you can do the same using update method and it will continue counting without dropping old counters for objects:
>>> from collections import Counter
>>> c = Counter(['hello', 'hello', 1])
>>> print c
Counter({'hello': 2, 1: 1})
>>> c.update(['hello'])
>>> print c
Counter({'hello': 3, 1: 1})
Solution 2:
print len(set(w.lower() for w in open('filename.dat').read().split()))
Reads the entire file into memory, splits it into words using whitespace, converts each word to lower case, creates a (unique) set from the lowercase words, counts them and prints the output
Solution 3:
If you want to get count of each unique word, then use dicts:
words = ['Hello', 'world', 'world']
count = {}
for word in words :
if word in count :
count[word] += 1
else:
count[word] = 1
And you will get dict
{'Hello': 1, 'world': 2}
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