我正在尝试用python实现一些快速的二进制求幂。我想知道数字的二进制表示返回1的整数。也许举个例子会更清楚:
bin(13) # returns 1101 because one 8 + one 4 + one 1 = 13. 我如何构建一个返回8,4,1的函数,将二进制数作为参数传递?正如你所看到的,我不是显式地试图得到2的幂,而是极简主义的表示法来将这些幂相乘。
发布于 2019-11-03 14:09:47
这个问题有点让人困惑(请看我的评论),但我还是想分享一个解决方案,因为目前接受的答案对我来说似乎令人费解。出于好奇心,我明天可能会比较和测试一堆不同的解决方案。
bin_num = bin(13)
def bin_str_decomp(bin_num_str):
bin_clean = bin_num_str[:1:-1]
return [1 << idx for idx, bit in enumerate(bin_clean) if bit == '1']
print(bin_str_decomp(bin_num))发布于 2019-11-03 07:14:37
你可以在下面这几行中做一些事情:
# Split the binary and grab interested part, and its size.
# >> bin(123456789) == "0b111010110111100110100010101"
binary = bin(123456789)[2:]
size = len(binary)
numbers = []
for i in range(size):
# Checks to see if the binary[i] is not equals to zero.
if binary[i] is not "0":
# Indexes the `binary` string and adds (size - i - 1) zeros to the end of it.
number = int(binary[i] + "0" * (size - i - 1), 2)
numbers.append(number)
print(numbers)
# >> [67108864, 33554432, 16777216, 4194304, 1048576, 524288, 131072, 65536, 32768, 16384, 2048, 1024, 256, 16, 4, 1]这里有一个更短的解决方案。
binary = bin(13)[2:]
nums = [
int(binary[i] + "0" * (len(binary) - i - 1), 2)
for i in range(len(binary))
if binary[i] is not "0"
]
return nums下面是单行解决方案,也是为了解决这个问题。
print((lambda binary: [int(binary[i] + "0" * (len(binary) - i - 1), 2) for i in range(len(binary)) if binary[i] is not "0"])(binary = bin(123456789)[2:]))https://stackoverflow.com/questions/58675946
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