A Counter is definitely the way to go about this. Just as a little more
information. The below example can be simplified:
from collections import Counter
count = Counter(mylist)
With the other example, you could have achieved the same thing (and been
backward compatible to python2.5) with
from collections import defaultdict
count = defaultdict(int)
for k in mylist:
count[k] += 1
On 4/25/13 9:16 PM, Modulok wrote:
On 4/25/13, Denis McMahon <denismfmcma...@gmail.com> wrote:
On Wed, 24 Apr 2013 22:05:52 -0700, CM wrote:
I have to count the number of various two-digit sequences in a list such
as this:
mylist = [(2,4), (2,4), (3,4), (4,5), (2,1)] # (Here the (2,4) sequence
appears 2 times.)
and tally up the results, assigning each to a variable.
...
Consider using the ``collections`` module::
from collections import Counter
mylist = [(2,4), (2,4), (3,4), (4,5), (2,1)]
count = Counter()
for k in mylist:
count[k] += 1
print(count)
# Output looks like this:
# Counter({(2, 4): 2, (4, 5): 1, (3, 4): 1, (2, 1): 1})
You then have access to methods to return the most common items, etc. See more
examples here:
http://docs.python.org/3.3/library/collections.html#collections.Counter
Good luck!
-Modulok-
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