CODEWITHSUNDEEP
pythonlist
ProperPenguin
ProperPenguin

Reputation: 13

Comparing a list to a tuple

Looking for the best way of doing this:

So i have a list containing unicode strings, lets call this listA

I have a list of tuples, each of the tuples contains a unicode string and an integer, lets call this listB

What i need to do is to find each of the strings in listA in listB's tuples. If its found then increment the integer in that tuple.

I can think of long ways to do this by creating a new list of tuples, but i'm not convinced this is the best way.

Any assistance gratefully received

Upvotes: 1

Views: 79

Answers (2)

m.wasowski
m.wasowski

Reputation: 6387

Use collections.Counter, you'll get result as dictionary:

from collections import Counter
txt = """Looking for the best way of doing this: 
    So i have a list containing unicode strings, lets call this listA I 
    have a list of tuples, each of the tuples contains a unicoe string 
    and an integer...
""".split() # this gives list of words

counter = Counter(txt)
for word, count in counter.items():
    print "{}: {}".format(word, count)

In fact counter.items() gives you tuples you need. Counter gives you much more, try stuff like counter.most_common()[:10] and have fun.

[edit] of course later you can increment values with counter.update(another_list_of_words).

Upvotes: 0

Ashwini Chaudhary
Ashwini Chaudhary

Reputation: 250891

You should use collections.Counter for this:

>>> from collections import Counter
>>> listA = ['a', 'b', 'c', 'a', 'c']
>>> listB = [('a', 5), ('b', 10), ('c', 0)]

Convert listB to a Counter object first:

>>> c = Counter(dict(listB))
>>> c
Counter({'b': 10, 'a': 5, 'c': 0})

Now update it with the count from listA:

>>> c.update(listA)
>>> c
Counter({'b': 11, 'a': 7, 'c': 2})

Upvotes: 3

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