1. while 循環
while循環用在有條件的控制上
while循環知道表達式爲假才退出
n = 10
while n<15:
n=n+1
print (n)
10到1循環遞減
n = 10
print ('###############script is start################')
while n>0:
print ('n =%s '%n)
n -= 1
print ('###############scipt is end###################')
2. for循環
在序列裏使用for循環遍歷
a = '1234'
for i in a:
print i
# 1+2+3+...+100=?
sum = 0
for i in range(1,101):
sum= sum + i
print sum
迭代遍歷:將序列中各個元素取出來。
dic1 = dict.fromkeys('abcd',100)
for k in dic1:
print k
小練習 9x9 乘法表:for i in xrange(1,10):
for j in xrange(1,i+1):
print ' %s * %s = %s ' % (j,i,j*i),
print
輸出結果爲:1 * 1 = 1
1 * 2 = 2 2 * 2 = 4
1 * 3 = 3 2 * 3 = 6 3 * 3 = 9
1 * 4 = 4 2 * 4 = 8 3 * 4 = 12 4 * 4 = 16
1 * 5 = 5 2 * 5 = 10 3 * 5 = 15 4 * 5 = 20 5 * 5 = 25
1 * 6 = 6 2 * 6 = 12 3 * 6 = 18 4 * 6 = 24 5 * 6 = 30 6 * 6 = 36
1 * 7 = 7 2 * 7 = 14 3 * 7 = 21 4 * 7 = 28 5 * 7 = 35 6 * 7 = 42 7 * 7 = 49
1 * 8 = 8 2 * 8 = 16 3 * 8 = 24 4 * 8 = 32 5 * 8 = 40 6 * 8 = 48 7 * 8 = 56 8 * 8 = 64
1 * 9 = 9 2 * 9 = 18 3 * 9 = 27 4 * 9 = 36 5 * 9 = 45 6 * 9 = 54 7 * 9 = 63 8 * 9 = 72 9 * 9 = 81
3. break 和 continue
for i in xrange(1,10):
if i >5:
break
print i,
for i in range(1,10):
if i == 6:
print ('6666')
continue
print i