python_109_切片补充和list函数

#切片补充
a=[1,2,3,4,5,6,7,8]
print(a[::2])#隔一个取一个元素   [1, 3, 5, 7]
print(a[::-1])#将列表或元祖颠倒过来   [8, 7, 6, 5, 4, 3, 2, 1]
b=tuple(a)
print(b)#(1, 2, 3, 4, 5, 6, 7, 8)
print(b[::2])#(1, 3, 5, 7)
print(b[::-1])#(8, 7, 6, 5, 4, 3, 2, 1)
c=list(b)
print(c[::3])#[1, 4, 7]
print(c[::-2])#[8, 6, 4, 2]
# list函数常用在数据处理中实体化迭代器或生成器
gen=range(10)
print(gen)#range(0, 10)
print(list(gen))#[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]