Ed Leafe wrote:
...
> There are probably several other ways to accomplish this task; I
> chose this one because it's very flexible. Try changing the value of
> 'flds' to any other value, and see how the output changes.
>
I did a quick test.
----------------------------------------------------------------
# t_ed.py
# Number of fields per record
flds = 3
data = ["%s" % i for i in range(3000000)]
def test_ed(data):
nthFields = [data[n::flds] for n in range(flds)]
recTuples = zip(*nthFields)
recs = [",".join(tup) for tup in recTuples]
output = "\n".join(recs)
file("data.txt", "w").write(output)
test_ed(data)
----------------------------------------------------------------
# t_ug.py
# Number of fields per record
#flds = 3
data = ["%s" % i for i in range(3000000)]
def test_ug(data):
alen = len(data)
i = 0
f = open("data.txt", "w")
while(i+3 <= alen):
f.write("%s,%s,%s\n" % (data[i], data[i+1], data[i+2]))
i = i+3
f.close()
test_ug(data)
----------------------------------------------------------------
Times for the two versions:
time python t_ed.py
real 0m27.093s
user 0m26.302s
sys 0m0.792s
time python t_ug.py
real 0m9.525s
user 0m8.985s
sys 0m0.536s
Plain loops are a lot faster and do not consume such a lot of memory.
Uwe
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