Repeating elements in list comprehension

问题:

I have this list comprehension:

[[x,x] for x in range(3)]

which results in this list:

[[0, 0], [1, 1], [2, 2]]

but what I want is this list:

[0, 0, 1, 1, 2, 2]

What's the easiest to way to generate this list?

回答1:

[y for x in range(3) for y in [x, x]]

回答2:

>>> [i for i in range(3) for _ in range(2)]
[0, 0, 1, 1, 2, 2]

回答3:

a general solution;

m = 3   #the list of integers
n = 2   # of repetitions
[x for x in range(m) for y in range(n)]

回答4:

>>> [int(x/2) for x in range(6)]
[0, 0, 1, 1, 2, 2]

回答5:

My solution:

def explode_list(p,n):
    arr=[]
    track=0

    if n==0:
        return arr    
    while track<len(p): 
        m=1
        while m<=n:
            arr.append(p[track])
            m=m+1
        track=track+1

    return arr

回答6:

You might get away with this:

[floor(x/2) for x in range(6)]

edit1

[int(x/2) for x in range(6)]

is the more portable solution in the same vein. Although the other presented answers seem better.

回答7:

[x/2 for x in range(6)]

update:

[x//2 for x in range(6)] #ok now ?