beginner <[EMAIL PROTECTED]> writes:
> On Oct 9, 3:53 pm, Alexander Schmolck <[EMAIL PROTECTED]> wrote:
>> beginner <[EMAIL PROTECTED]> writes:
>> how about:
>>
>> ratio = (lambda c: c.real/c.imag)(sum(complex(r["F1"], r["F2"] for r in
>> rec)))
>>
> Neat, but I will have a problem if I am dealin
On Oct 9, 3:53 pm, Alexander Schmolck <[EMAIL PROTECTED]> wrote:
> beginner <[EMAIL PROTECTED]> writes:
> > Hi All,
>
> > I have a list of records like below:
>
> > rec=[{"F1":1, "F2":2}, {"F1":3, "F2":4} ]
>
> > Now I want to write code to find out the ratio of the sums of the two
> > fields.
>
>
beginner <[EMAIL PROTECTED]> writes:
> Hi All,
>
> I have a list of records like below:
>
> rec=[{"F1":1, "F2":2}, {"F1":3, "F2":4} ]
>
> Now I want to write code to find out the ratio of the sums of the two
> fields.
>
> One thing I can do is:
>
> sum(r["F1"] for r in rec)/sum(r["F2"] for r in re
Matt Nordhoff wrote:
Chris Rebert wrote:
I personally would probably do:
from collections import defaultdict
label2sum = defaultdict(lambda: 0)
FWIW, you can just use:
label2sum = defaultdict(int)
You don't need a lambda.
Indeed, in this case, with two known keys, the defaultdict is not
FB:
> def add_r( sums, r ): return sums[0]+r['F1'], sums[1]+r['F2']
> sum_f1, sum_f2 = reduce( add_r, rec, (0,0) )
> result = sum_f1/sum_f2
Until this feature vanishes I think it's better to use it (untested):
add_r = lambda (a, b), r: (a + r['F1'], b + r['F2'])
Bye,
bearophile
--
http://mail.py
On 8 Ott, 22:23, beginner <[EMAIL PROTECTED]> wrote:
> Hi All,
>
> I have a list of records like below:
>
> rec=[{"F1":1, "F2":2}, {"F1":3, "F2":4} ]
>
> Now I want to write code to find out the ratio of the sums of the two
> fields.
>
> One thing I can do is:
>
> sum(r["F1"] for r in rec)/sum(r["F
Chris Rebert wrote:
> I personally would probably do:
>
> from collections import defaultdict
>
> label2sum = defaultdict(lambda: 0)
FWIW, you can just use:
label2sum = defaultdict(int)
You don't need a lambda.
> for r in rec:
> for key, value in r.iteritems():
> label2sum[key] +=
beginner:
> I can of course use an old-fashioned loop. This is more readable, but
> also more verbose.
> What is the best way, I wonder?
In such situation the old loop seems the best solution. Short code is
good only when it doesn't make the code too much slow/difficult to
understand. Keeping the
I personally would probably do:
from collections import defaultdict
label2sum = defaultdict(lambda: 0)
for r in rec:
for key, value in r.iteritems():
label2sum[key] += value
ratio = label2sum["F1"] / label2sum["F2"]
This iterates through each 'r' only once, and (imho) is pretty
read
beginner a écrit :
Hi All,
I have a list of records like below:
rec=[{"F1":1, "F2":2}, {"F1":3, "F2":4} ]
Now I want to write code to find out the ratio of the sums of the two
fields.
One thing I can do is:
sum(r["F1"] for r in rec)/sum(r["F2"] for r in rec)
But this is slow because I have
Hi All,
I have a list of records like below:
rec=[{"F1":1, "F2":2}, {"F1":3, "F2":4} ]
Now I want to write code to find out the ratio of the sums of the two
fields.
One thing I can do is:
sum(r["F1"] for r in rec)/sum(r["F2"] for r in rec)
But this is slow because I have to iterate through th
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