1.for迴圈

a =0
for b in range(101):
     a =a +b
print a

>>> list (range(5))
[0, 1, 2, 3, 4]

2.while迴圈

>>> sum = 0
>>> n= 99
>>> while n>0:
...     sum =sum + n
...     n = n-2
... 
>>> print sum
2500

3.break

n = 1
while n <= 100:
    if n > 10: # 當n = 11時，條件滿足，執行break語句
        break # break語句會結束當前迴圈
    print(n)
    n = n + 1
print('END')

4.continue

n = 0
while n < 10:
    n = n + 1
    if n % 2 == 0: # 如果n是偶數，執行continue語句
        continue # continue語句會直接繼續下一輪迴圈，後續的print()語句不會執行
    print(n)