[Tutor] Nested list comprehensions

[John Fouhy]

On 15/05/06, Kent Johnson <kent37 at tds.net> wrote:
> You can come pretty close with generators, though it hurts to think
> about what is actually going on behind the scenes here:
>
> In [1]: import itertools
>
> In [2]: def fibs():
>     ...:     yield 0
>     ...:     yield 1
>     ...:     fib1 = fibs()
>     ...:     fib2 = fibs()
>     ...:     fib2.next()
>     ...:     for a, b in itertools.izip(fib1, fib2):
>     ...:         yield a+b

Yikes!

f = fibs()
for i in range(100):
    start = time.clock()
    x = f.next()
    dur = time.clock() - start
    print i, x, dur
    if dur > 10:
        break

0 0 2.03936533833e-005
1 1 5.5873022968e-006
2 1 1.59238115459e-005
3 2 1.25714301678e-005
4 3 1.95555580388e-005
5 5 2.15111138427e-005
6 8 2.93333370582e-005
7 13 6.06222299203e-005
8 21 7.87809623849e-005
9 34 0.000119568269152
10 55 0.000383568302675
11 89 0.000409269893241
12 144 0.000650082622233
13 233 0.000979454092629
14 377 0.00172200656787
15 610 0.00713330884232
16 987 0.00450979104886
17 1597 0.0128720270314
18 2584 0.0150373860365
19 4181 0.0283779083654
20 6765 0.0490199173359
21 10946 0.135228918759
22 17711 0.240615497221
23 28657 0.365666586116
24 46368 0.827867508301
25 75025 2.14721368219
26 121393 4.08266218193
27 196418 20.1769099145

Hmm, do you know an easy way to check how much memory python is using?
 My HDD was swapping like crazy by the end of that..

-- 
John.