So I'm just wanting to do:

f = open(infile)
md = max([int(x) for x in f.readlines()[1:]])
f.close()

but it seems to be running much slower than I was expecting. If I split this up into steps and time each one, thusly:

f = open(infile)
start=time.clock()
data = f.readlines()
print time.clock()-start
start=time.clock()
idata = [int(x) for x in data[1:]]
print time.clock()-start
start=time.clock()
md = max(idata)
print time.clock()-start
f.close()

I find that the conversion of text to integers takes 4 times as long as reading in the data from the disk! Specifically, for a 1.4 million entry array, it takes ~0.2-0.3 seconds to read in the data, and 0.9-1 seconds to do the conversion, and ~0.06 seconds to find the maximum value.

Are there any tricks to more directly or efficiently read in a list of integers in Python? I have ~2500 files to read in, and at >1 second each that's coming up close to an hour, which is fine, but it seems like it shouldn't need to take that long. Unless there's a neat Python trick, I might have to resort to Fortran :P