12-python入门1
内存管理: python 变量重新赋值之后,对应的内存地址会变
引用计数
del是解除绑定
内存地址复用
>>> x=1
>>> id(x)
9310240
>>> x=2
>>> id(x)
9310272
>>> y=1
>>> id(y)
9310240
字符串格式化控制符
print('用户名是: %s 密码是: %s' %)
使用while循环打印1 2 3 4 5 6 8 9 10
x = 1
print('Now, Print the numbers: ', end=' ')
while x < 11:
print(x, end=' ')
if x == 6:
x += 2
print(" ", end='')
else:
x += 1
方法二
print('\n')
x = 0
while x < 10:
x += 1
if x == 7:
continue
print(x, end=' ')
求1-100的和
print('\n')
y = 1
sum = 0
while y < 101:
sum += y
y += 1
print('1-100的所有数的和是:', sum)
print('\n')
求 1-100内所有的偶数
print('100以内所有的偶数: ', end='')
for i in range(1, 101):
if i % 2 == 0:
print(i, end=' ')
求100以内的奇数
print('\n')
print('100以内所有的奇数: ', end=' ')
for ii in range(1, 101):
if ii % 2 != 0:
print(ii, end=' ')
print('\n')
求1-2+3-4+5 ... 99的所有数的和
sum = 0
for i in range(1, 100):
if i % 2 == 0:
sum -= i
print('-', i, end='')
else:
sum += i
print('+', i, end='')
print('=', sum)
用户登陆(三次机会重试)
username = ('cx2c')
password = ('cx2c')
for i in range(1,4):
user=input('Please Input Your Name: ')
pasw=input('Please Input Your Password: ')
if username == user and password==pasw:
print('Login in successful')
break
else:
print('The %sth time False,Try Again' %i)
打印结果
Now, Print the numbers: 1 2 3 4 5 6 8 9 10
1 2 3 4 5 6 8 9 10
1-100的所有数的和是: 5050
100以内所有的偶数: 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100
100以内所有的奇数: 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99
+ 1- 2+ 3- 4+ 5- 6+ 7- 8+ 9- 10+ 11- 12+ 13- 14+ 15- 16+ 17- 18+ 19- 20+ 21- 22+ 23- 24+ 25- 26+ 27- 28+ 29- 30+ 31- 32+ 33- 34+ 35- 36+ 37- 38+ 39- 40+ 41- 42+ 43- 44+ 45- 46+ 47- 48+ 49- 50+ 51- 52+ 53- 54+ 55- 56+ 57- 58+ 59- 60+ 61- 62+ 63- 64+ 65- 66+ 67- 68+ 69- 70+ 71- 72+ 73- 74+ 75- 76+ 77- 78+ 79- 80+ 81- 82+ 83- 84+ 85- 86+ 87- 88+ 89- 90+ 91- 92+ 93- 94+ 95- 96+ 97- 98+ 99= 50
Please Input Your Name: cx2c
Please Input Your Password: cc
False
Please Input Your Name: cx2c
Please Input Your Password: cx2c
Login in successful