Python的循环有两种：

for...in循环

#把list或tuple中的每个元素迭代出来
names = ['Michael', 'Bob', 'Tracy']
for name in names:
    print(name)

#range(101)就可以生成0-100的整数序列，计算如下：
sum = 0
for x in range(101):
    sum = sum + x
print(sum)

while循环

sum = 0
n = 99
while n > 0:
    sum = sum + n
    n = n - 2
print(sum)