On 2/19/2010 3:02 PM, MRAB wrote:
Is this any better?
def read_data_file(filename):
reader = csv.reader(open(filename, "U"),delimiter='\t')
data = []
for row in reader:
if '[MASKS]' in row:
break
data.append(row)
As noted in another thread recently, you can save time by *not* looking
up the "append" method of the list object each time through the FOR loop:
data = []
app_method = data.append
for row in reader:
if '[MASKS]' in row:
break
app_method(row)
Similarly in the rest of the code. This technique improved performance
about 31% in this test:
#--------------------
import timeit
tt = timeit.repeat("for i in xrange(1000000): mylist.append(i)",
"mylist=[]",
number=25)
print "look up append() method each time:", min(tt)
tt = timeit.repeat("for i in xrange(1000000): app(i)",
"mylist=[]; app = mylist.append",
number=25)
print "look up append() method just once:", min(tt)
#--------------------
output:
look up append() method each time: 8.45481741783
look up append() method just once: 5.84429637887
-John
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