将列表转换为由其元素组成的数字

Question

I'd like to convert a list, for example [1,0,1,0] to the number 1010 (type int ). Moreover, I'd like to do it within a function, so not using return . Is it possible and how can I do it?

Answer 1

def convert_list_of_ints_to_int( lst ):
   return reduce(lambda x, y: x*10 + y, lst)

Answer 2

I would recommend

def concat_list(inlist):
    return sum(10**pwr*elem for pwr, elem in enumerate(inlist[::-1]))

in verbose form

def concat_list(inlist):
    res = inlist[0]
    for elem in inlist[1:]:
        res=res*10+elem
    return res

Answer 3

IMHO, @JonClements' comment is clearly the most pythonic answer:

int(''.join(map(str, some_list)))

Though I'd use a generator-comprehension, which is generally preferable over map , and is more readable:

int(''.join( str(num) for num in some_list ))

Answer 4

Here is another solution, using numpy . I don't claim it is better than any of the other answers, but I find it cool nevertheless.

a = [1,0,1,0]
( a * 10**numpy.arange(len(a))[::-1] ).sum()
=> 1010