On 05/18/2016 09:53 PM, DFS wrote:
On 5/18/2016 10:58 PM, Larry Hudson wrote:
[snip...]
Why two loops? Put both summations in a single loop. Then you're only
scanning the alist once instead of twice.
groups1 = defaultdict(int)
groups2 = defaultdict(int)
for nm, matches, words in alist:
groups1[nm] += matches
groups2[nm] += words
-=- Larry -=-
That gives me two lists - how do I combine them?
In the end that'll be at least 6 lines of code. Do you have a one-liner to
summarize the data?
Thanks
One-liner? No way. I did manage to get the whole conversion down to 6 lines...
(And I am far from an expert pythonista, a more experienced/expert programmer can probably do
better.)
A two-line helper function
A two-line for loop
A one-line list comprehension
One line to declare a dictionary as an intermediate variable
# A helper function -- adds two tuples
# Could add square brackets to return a 2-element list instead of
# a tuple, but the final result is the same either way.
def addtpl(t1, t2):
return t1[0]+t2[0], t1[1]+t2[1]
# Accumulate alist data into an intermediate temporary dictionary
tdic = {}
for dat in alist:
tdic[dat[1]] = addtpl(tdic.get(dat[1], (0,0)), dat[2:])
# Convert the dictionary back to a list of tuples
result = [(str(n), tdic[n][0], tdic[n][1]) for n in tdic]
Of course, this doesn't retain the original order, but you can use the sorted() function to sort
the results by the names.
Here is the same thing as a single function that returns the sorted list...
(It also automatically throws away the temporary dictionary. But it's now 7 lines because of
the added def line.)
def combine(lst):
def addtpl(t1, t2):
return [t1[0]+t2[0], t1[1]+t2[1]
tdic = {}
for dat in lst:
tdic[dat[1]] = addtpl(tdic.get(dat[1], (0,0)), dat[2:])
return sorted([(str(n), tdic[n][0], tdic[n][1]) for n in tdic])
-=-Larry -=-
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