列表理解，用于将字符串列表转换为int和float列表

Question

I have a list of lists. The sublists each contain three strings.

bins = [['1', '2', '3.5'], ['4', '5', '6.0']]

I need to convert this into a lists of lists where each sublist consists of two integers and a float. I was thinking of a list comprehension along the lines of:

[ [int(start), int(stop), float(value)] for bn in bins for [start, stop, value] in bn]

Answer 1

You're close:

[[int(start), int(stop), float(value)] for start, stop, value in bins]

You don't need the bn variable to hold each bin or a loop to iterate through its contents; each bin can be unpacked directly into the three variables.

Answer 2

Another option is using map

>>> bins = [['1', '2', '3.5'], ['4', '5', '6.0']]
>>> map(lambda x: [int(x[0]), int(x[1]), float(x[2])], bins)
[[1, 2, 3.5], [4, 5, 6.0]]