Day2_03_python基础知识 <for 循环>

import random
num = random.randint(10,20)
print(num)
for i in range(0,num):
    print(i)
遍历字符串
a = 'zholi'
for i in a:
    print(i)

遍历数组：
a = ['a',34,'bn','哈哈']
for i in a:
    print(i)

遍历字典所有的key
dict = {'a1':'b1','a2':'b2','a3':'b3'}
dict1 = {'k1':'k2'}
for i in dict:
    print(i)
输出：
    a1
    a2
    a3

遍历字典中，所有的value
for i in dict:
    print(dict.get(i))
输出：
    b2
    b3
    b1

遍历字典所有的key，value
这种方式可以保证key,value一一对应输出
for i in dict:
    print(i,dict.get(i))
输出：
a1 b1
a2 b2
a3 b3

for嵌套循环
for a in range(10):
    for b in range(10):
        print("%s * %s = %s"%(a,b,a*b),end='
')
    print()

for 循环，打印三角形
for a in range(6):
    for b in range(0,a):
        print('# ',end=' ')
    print()

for 循环打印正方形
for a in range(4):
    for b in range(4):
        print('*',end=' ')
    print()

for循环打印乘法口诀
for a in range(0,10):
    for b in range(1,a+1):
        print('%s*%s=%s'%(b,a,a*b),end=' ')
    print()

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