python 基础复习 02
1 #逻辑运算 2 # and or not 3 #优先级, () > not > and > or 如果同一优先级 从左到右依次计算 4 # print(2 > 1 and 1 < 4 or 2 < 3 and 9 > 6 or 2 < 4 and 3 < 2) 5 #先看 and 三个and 依次是 T or T or F 6 #然后再看 or T 和 T 是 真 T or F 最后是真 7 8 # print(3 > 4 or 4 < 3 and 2 == 2) 9 # print(1 < 2 and 3 < 4 or 1 > 2) 10 # print(2 > 1 and 3 < 4 or 4 > 5 and 2 < 1) 11 # print(1 > 1 and 3 < 4 or 4 > 5 and 2 > 1 and 9 > 8 or 7 < 6) 12 #F or F and T or F 13 #F or F or F 14 15 """ 16 x or y x为非零 则返回x 若x为0 则返回y 17 18 int 转换成 bool 非零转换成bool 为 True 0 转换成bool 是False 19 """ 20 # print(1 or 2) 1 21 # print(3 or 2) 3 22 # print(0 or 2) 2 23 # print(100 or 3) 100 24 # print(0 or 23) 23 25 # print(bool(2)) # True 26 # print(bool(-2)) # True 27 # print(bool(0)) # False 28 29 #bool ---> int 30 # print(int(True)) # 1 31 # print(int(False)) # 0 32 33 """x or y x 为 True 则返回x""" 34 # print(2 or 100 or 3 or 4) # 2 35 36 """x and y x True , 则返回 y """ 37 # print(1 and 2 ) 38 # print(0 or 4 and 3 or 2) # 3 39 # print(1 > 2 and 3 or 4 and 3 < 2) # False 40 # print(2 or 1 < 3 and 2) # 2 41 42 """ x or y x 为 True 则返回 x """ 43 """ x and y x 为 True 则返回 y """ 44 # print(6 or 2 > 1) # 6 先看 > < 45 # print(3 or 2 > 1) # 3 46 # print(0 or 5 < 4) # False 47 # print(5 < 4 or 3) # 3 48 # print(2 > 1 or 6) # True 49 # print(3 and 2 > 1) # True 50 # print(0 and 3 > 1) # 0 51 # print(2 > 1 and 3) # 3 52 53 1 # 小练习 用户登陆 有三次输入机会 54 2 username = "蜘蛛" 55 3 password = "123" 56 4 i = 3 57 5 while i > 0: 58 6 user = input("请输入您的账号:") 59 7 i -= 1 60 8 if user == username: 61 9 passwd = input("请输入您的密码:") 62 10 if passwd == password: 63 11 print("验证成功,正在登陆...") 64 12 print("""恭喜你登陆成功! 65 13 用户名:%s 66 14 密码:%s 67 15 """%(user,passwd)) 68 16 break 69 17 else: 70 18 if i == 0: 71 19 print("您的机会已经没有了!gameover 下次见。") 72 20 answer = input("是否想再试试?Yes") 73 21 if answer == "Yes": 74 22 i = 3 75 23 print("密码错误,请重新输入:") 76 24 print("你还有"+str(i)+"次机会") 77 25 else: 78 26 print("请输入正确的用户名!") 79 27 if i == 0: 80 28 print("您的机会已经没有了!") 81 29 answer = input("是否还想再试试?请输入:Yes") 82 30 if answer == "Yes": 83 31 i = 3 84 32 print("您还有"+str(i)+"次机会") 85 33 else: 86 34 print("您该歇歇了...") 87 88 """ 89 数据类型: 90 int 91 方法: 92 bit_length 93 """ 94 # i = 4 95 # print(i.bit_length()) # 3 96 97 """ 98 bit_length 99 1 0000 0001 1 100 2 0000 0010 2 101 3 0000 0011 2 102 4 0000 0100 3 103 """ 104 105 106 """ 107 bool True False 108 109 int ---> str 110 i = 1 111 s = str(i) 112 print(s) 113 114 str ---> int (只能是数字 不能是字母) 115 s = "234" 116 a1 = int(s) 117 print(a1) 118 119 int ---> bool 120 i = 3 121 b = bool(i) 122 print(b) # True 123 124 --->(转化) 125 bool ---> int 126 True 1 127 False 0 128 129 130 str ---> bool 131 s = ""(空字符串)---->(False) 132 非空字符串都是True 133 134 s = " " 135 d = bool(s) 136 print(d) # True 137 a = "" 138 c = bool(a) 139 print(d) # False 140 """ 141 142 #字符串的索引与切片 143 s = "QAZWSXEDCrfvedc" 144 # s1 = s[1] 145 # print(s1) # A 146 # s2 = s[0] 147 # print(s2) # Q 148 # s3 = s[8] 149 # print(s3) 150 # s4 = s[0:] 151 # print(s4) 152 # s5 = s[0:4] # 顾头不顾尾 153 # print(s5) 154 # s6 = s[0:5] 155 # print(s6) 156 # s7 = s[-1] 157 # print(s7) 158 # s8 = s[-2] 159 # print(s8) 160 # s9 = s[0:-1] # 也是顾头不顾尾 161 # print(s9) 162 # 163 # q = s[:] 164 # print(q) 165 166 # s = "QAZWSXEDCrfvedc" 167 # a1 = s[0:7:3] 168 # print(a1) 169 170 # a2 = s[5:0:-1] 171 # print(a2) # 倒着来 XSWZA 172 # a3 = s[5::-1] 173 # print(a3) # XSWZAQ 174 # a4 = s[-1::-1] 175 # print(a4) # 字符串所有元素 倒着排列
"""
字符串的操作
"""
1 # s = "qazwsx" 2 # s1 = s.capitalize() # 首字母大写 3 # print(s1) 4 # 5 # s2 = s.upper() # 都大写 6 # print(s2) 7 # s3 = s2.lower() # 都小写 8 # print(s3)
1 #输入验证码,不区分大小写 2 3 s_str = "asdQAZ" 4 you_input = input("请输入’asdQAZ‘,不区分大小写") 5 if s_str.upper() == you_input.upper(): 6 print("输入成功") 7 else: 8 print("请重新输入")
1 # 大小写翻转 2 # s = "qazAZ" 3 # s3 = s.swapcase() 4 # print(s3) 5 6 #每个隔开(特殊字符或者数字)的单词首字母大写 7 # s = 'lizy waws' 8 # a1 = s.title() 9 # print(a1) 10 11 # w = "fade hello,edc/rew8tre_bvc" 12 # a2 = w.title() 13 # print(a2) 14 15 16 17 # center 居中 20 是总长度 18 # s = "hellopython" # ' hellopython ' 19 # a1 = s.center(20, "#") # 总长度 20 用#号来填充 20 # print(a1) 21 22 23 24 # s = "lizyPYTHON" 25 # a1 = s.startswith("lizy") #以...开头 26 # print(a1) # True 27 28 29 30 #find 通过元素找索引,找不到返回-1 31 32 #index 通过元素找索引,找不到报错 33 # s = "lizyPYTHon" 34 # a1 = s.find("z") # 2 35 # a2 = s.index("S") # 报错 36 # print(a1) 37 # print(a2) 38 39 # strip左右一起删除 rstrip :从右开始删除 lstrip:从左开始删除 40 41 # s = " lizy " 42 # a1 = s.strip() # 去空格 43 # print(a1) 44 45 # s = " lizy " 46 # a2 = s.rstrip() # 去右边空格 47 # print(a2) 48 49 # s = "lizy ll l" 50 # a3 = s.count("l") # count 查看元素的个数 51 # print(a3) 52 53 # s = ":lizy:wufa:chenggong" 54 # a1 = s.split(":") # split 分隔符 ** str ---> list 字符串转换成列表 55 # print(a1) # 返回 ['', 'lizy', 'wufa', 'chenggong'] 56 57 58 # format的三种玩儿法 格式化输出 59 # 第一种 60 # s = "我叫{}, 今年{}, 爱好{}, 再说一下我叫{}".format("蜘蛛", 23, "旅行", "蜘蛛") 61 # print(s) 62 63 #第二种 大括号里写索引 一定得按顺序写 64 # s = "我叫{0}, 今年{1}, 爱好{2}, 再说一下我叫{0}".format("蜘蛛", 23, "旅行") 65 # print(s) 66 67 #第三种 按照键值对的形式来写 顺序无所谓 68 # s = "我叫{name}, 今年{age}, 爱好{hobby}, 再说一下我叫{name}".format(name="蜘蛛", hobby="旅行", age=23) 69 # print(s) 70 71 #如果要替换一个的话 replace("原内容","替换后的内容",1) 加数字 72 #replace 替换 默认全部替换 replace("原内容","替换后的内容") 73 # s = "伍佰谓和句孙女士的举动看到你我孙女士" 74 # a1 = s.replace("孙女士", "王女士") 75 # print(a1)
注:本文是根据老男孩课程内容整理而成的,本文仅供个人笔记使用,如果有侵犯,请联系我,我立即撤销。