列表的循环遍历
为了更有效的输出列表中的数据，我们可以采用循环的方式完成。
for循环方式：
name = ['xiaoming','xiaoli','xiaozhang','xiaowang']
for x in name:
print(x)
结果为：
xiaoming
xiaoli
xiaozhang
xiaowang
while循环方式：
name = ['xiaoming','xiaoli','xiaozhang','xiaowang']
length = len(name)
i = 0
while i < length:
print(name[i])
i += 1
结果为：
xiaoming
xiaoli
xiaozhang
xiaowang
