day3 ord,chr,random,string

day3复习

>>> for i in range(10):

... if i == 3:

... break

... print(i)

...

0

1

2

>>> for i in range(10):

... if i == 3:

... continue

... print(i)

...

0

1

2

4

>>> while True:

... i = int(input("请输入一个数字："))

... if i%2 == 0:

... print("偶数")

... else:

... print("奇数")

... if i == 100:

... break

 

>>> ord("杜")

26460

>>> chr(26460)

'杜'

>>> d = "杜崇崇"

>>> type(d)

<class 'str'>

>>> d.encode("gbk")

b'\xb6\xc5\xb3\xe7\xb3\xe7'

>>> d.encode("utf8")

b'\xe6\x9d\x9c\xe5\xb4\x87\xe5\xb4\x87'

>>> type(d.encode("gbk"))

<class 'bytes'>

>>> type(d.encode("gbk").decode("gbk"))

<class 'str'>

unicode 不能直接写入文件也不能直接在网络传输，必须是bytes

练习1：

>>> a = "测试"

>>> type(a)

<class 'str'>

>>> a.encode("gbk")

b'\xb2\xe2\xca\xd4'

>>> type(a.encode("gbk"))

<class 'bytes'>

>>> type(a.encode("gbk").decode("gbk"))

<class 'str'>

 

encode 将str（unicode） 转为bytes类型

decode 将bytes类型转为str(unicode)类型

import random

a = [1,2,4,"as","ba"]

random.random() # 随机小数

100+random.random() # 整数+小数

random.randint(1,100) # 随机1,100之间的整数

random.choice() # 随机一个列表里面的值

random.uniform(1,100) # 随机1,100之间的小数点数

random.shuffle(a) # 随机对列表的顺序进行打乱

练习2：随机生成一个小写字母

chr(random.randint(97,123))

chr(97+random.randint(1,25))

 

chr(ord("A")+random.randint(1,25))

生成随机的10位小写字母：

s = ""

for i in range(10):

... ss = chr(ord("a")+random.randint(1,25))

... s+=ss

生成随机的10位小写字母：

for i in range(10):

... ss = chr(ord("A")+random.randint(1,25))

... s+=ss

生成随机的5个小写字母和5个大写字母：

>>> for i in range(5):

... s+= chr(ord("a")+random.randint(1,25))

...

>>> for i in range(5):

... s+= chr(ord("A")+random.randint(1,25))

 

生成随机不限定固定大小写个数的10个字母：

lower_num = random.randint(1,9)

uper_num = 10-lower_num

for i in range(lower_num):

s+= chr(ord("a")+random.randint(1,25))

for i in range(uper_num ):

s+= chr(ord("A")+random.randint(1,25))

 

>>> lower_case = string.ascii_lowercase

>>> lower_case

'abcdefghijklmnopqrstuvwxyz'

>>> low_list = list(lower_case)

>>> low_list

['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']

>>> low_list_s = low_list[:10]

>>> low_list_s

['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j']

>>> "".join(low_list_s)

'abcdefghij'

>>>

 

>>> letters = string.ascii_letters

>>> letters

'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'

>>> letters_list = list(letters)

>>> random.shuffle(letters_list)

>>> letters_list

['Q', 'Y', 'V', 'q', 'g', 'p', 'K', 'a', 'T', 'X', 's', 'U', 'H', 'N', 't', 'i', 'b', 'n', 'r', 'h', 'G', 'f', 'd', 'O', 'j', 'A', 'P', 'F', 'R', 'l', 'x', 'z', 'J', 'c', 'E', 'e', 'k', 'o', 'Z', 'D', 'y', 'M', 'I', 'C', 'W', 'w', 'S', 'L', 'v', 'B', 'u', 'm']

>>> "".join(letters_list[] )

KeyboardInterrupt

>>> "".join(letters_list[:10])

'QYVqgpKaTX'

 

>>> [random.choice(list(string.ascii_letters)) for i in range(1,9)]

['Y', 'g', 'y', 'j', 'G', 'K', 'I', 's']

>>> [random.choice(list(string.ascii_letters)) for i in range(10)]

['M', 'q', 'y', 'x', 'I', 'F', 'I', 'W', 'm', 's']

>>> "".join([random.choice(list(string.ascii_letters)) for i in range(10)])

'RZqoHNduTe'