列表生成式

 

 

In [6]: a = [i for i in range(1,10)]

In [7]: a
Out[7]: [1, 2, 3, 4, 5, 6, 7, 8, 9]

In [8]: a = [6 for i in range(1,10)]

In [9]: a
Out[9]: [6, 6, 6, 6, 6, 6, 6, 6, 6]

In [10]: a = [i for i in range(1,10) if i%2==0]

In [11]: a
Out[11]: [2, 4, 6, 8]

In [13]: a = [i for i in range(1,10) for j in range(2)]

In [14]: a
Out[14]: [1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9]

In [20]: a = [(i,j) for i in range(3) for j in range(2)]

In [21]: a
Out[21]: [(0, 0), (0, 1), (1, 0), (1, 1), (2, 0), (2, 1)]

In [22]: a = [(i,j,k) for i in range(3) for j in range(2) for k in range(3)]

In [23]: a
Out[23]: 
[(0, 0, 0),
 (0, 0, 1),
 (0, 0, 2),
 (0, 1, 0),
 (0, 1, 1),
 (0, 1, 2),
 (1, 0, 0),
 (1, 0, 1),
 (1, 0, 2),
 (1, 1, 0),
 (1, 1, 1),
 (1, 1, 2),
 (2, 0, 0),
 (2, 0, 1),
 (2, 0, 2),
 (2, 1, 0),
 (2, 1, 1),
 (2, 1, 2)]