On Thu, 13 Dec 2007, Nils Wagner apparently wrote: > How can I do that on-the-fly ? That depends on the file format. But are you just asking if you can do the following? data = [] for row in open(filename,'r'): r0, r1, r2 = row.split() data.append( [int(r0), int(r1), float(r2)] ) Cheers, Alan Isaac