有没有比这行代码更聪明/更快/更轻巧的替代品？

Question

file = [float(line.partition(' ')[0]) for line in file]

文件是打开文件的对象。。。在

thnq公司

Answer 1

有关速度的测量，请参见Python标准库模块timeit:

$ python -m timeit -s 'f = file("/tmp/numbers.txt")' '[float(line.partition(" ")[0]) for line in f]'
10000000 loops, best of 3: 0.123 usec per loop
$ python -m timeit -s 'f = file("/tmp/numbers.txt")' '[float(line.split(" ")[0]) for line in f]'
10000000 loops, best of 3: 0.132 usec per loop
$ python -m timeit -s 'f = file("/tmp/numbers.txt")' '[float(line.split(" ", 1)[0]) for line in f]'
10000000 loops, best of 3: 0.127 usec per loop

partition似乎至少比split快。我现在想不出更快的办法了，干得好。在