索引
#1.比较运算符======>返回的是布尔值# a = 6
# b = 8
# print(a > b)#False
# print(a != b)#true
# print(a < b)#true
#2.逻辑运算符 and or not======>返回的是布尔值
# a = 5
# b = 5
# c = 3
# print(a >b and b>c)#false
# print(a == b or a < c)#true
# print(not a > b)#true
# print(not b!=c)#false
#3.成员运算符=======>返回布尔值
#int类型
# list1 = ["xian","today",110]
# print(110 in list1)#true
# print ("today" not in list1)#false
# if 110 in list1:
# print("测试成功")
# else:
# print("测试失败")
#4.python中的位运算符
'''存储单位
1TB =1024 GB
1GB = 1024 MB
1MB = 1024 KB
1KB = 1024 BIYE
1 BIYE = 8 BIT 比特位是计算机中最小的存储单位，由8位0或者是1组成
0 0000 0 0 0=======>二进制
128 64 32 16 8 4 2 1=======>十进制中的数值'''
#①与运算符：&
a = 4
b = 5
# a : 00000100
# b : 00000101
# & : 00000100
# print(a & b)#4
#②或运算符：|
# | ：00000101
# print(a | b)#5
# ③异或运算符：^
# ^ : 00000001
# print(a ^ b)#1
# ④取反运算符：~
# ~ a : -(a+1)
# print(~ a )
# ⑤左移动运算符：<<
# a : 00000100
# << : 00010000
# print(a << 2)#16
# ⑥右移动运算符：>>
# >> : 00000001
# print(a >> 2)#1
# 小练习：
# a = 8
# b = 24
# print(a & b)#8
# print(a | b)#24
# print(a ^ b)#16
# print(~ b)#-25
# print(a << 3)#64
# print(b >> 3)#3
#5.python 中的索引
# 通过索引来取序列（字符串str，列表list，元组tuple）中的值
# 索引格式：str1
# ①.正向索引：从0开始，从左到右取值
# ②.负向索引：从-1开始，从右到左取值
# str1 = "today is monday"
# print(str1)#y
# print(str1[-4])#n
# print(str1)#超出范围
# print(str1[-16])#超出范围
#6.python中的切片
# ①切片
#切片的表达式：====>[开始索引：结束索引：步长]
# str1 ="hello word"
# print(str1)#ello
# print(str1[-3:-1])#or
# print(str1[-1:-3:-1])#dr
# print(str1[::])#展示全部
# print(str1[::-1])
# ②跳切
# print(str1)#l
# print(str1[-6:-3:2])#ow
# print(str1[::-2])#do le
#7.python中的字符串函数
#①字符串首字符大写：capitallize()
# str1 = "good luck"
# print(str1.capitalize())#Good luck
# ②单词首字母大写：title()
# str1 = "good luck"
# print(str1.title())#Good Luck
# ③统计字符串中字符出现的次数：count()
# str1 = "good luck"
# print(str1.count("o"))#2
# ④按照自定义的符号将字符串中的所有元素相连：join()
# str1 = "good luck"
# print("*".join(str1))#g*o*o*d* *l*u*c*k
# 把列表中的元素用空字符连接在一起(只能是str类型）:join()
# list1 = ["hello","word"]
# print("".join(list1))#helloword
# ⑤根据字符串的某个字符进行分割:split()
# str1 = "good luck"
# print(str1.split(" "))#['good', 'luck']
# list1 = str1.split(" ")
# print(list1)#['good', 'luck']
# print("".join(list1))#goodluck
# 小练习：
# 把字符串str1 = "xiaozhang_cute"输出成XiaozhangCute
# str1 = "xiaozhang_cute"
# print(str1.title())#Xiaozhang_Cute
# str2 = str1.title()#单词首字母大写
# print(str2.split("_"))#['Xiaozhang', 'Cute']把字符串分割成列表
# list1 = str2.split("_")#['Xiaozhang', 'Cute']
# print("".join(list1))#XiaozhangCute
# 8.删除字符串开头与结尾的字符
# str1 = "you don't want study"
# print(str1.strip("y"))#ou don't want stud
# print(str1.strip("you"))#don't want stud
#9.删除字符串开头有ab序列的字符：lstrip()
# str1 = "day is monday"
# print(str1.lstrip("day"))#is monday
# print(str1.lstrip("da"))# y is monday
#10.删除字符串结尾有ab序列的字符：rstrip()
# str1 = "day is monday"
# print(str1.rstrip("day"))#day is mon
#11.判断字符串是否以什么开始 ： startswith()======>返回布尔值
# str1 = "day is monday"
# print(str1.startswith("d"))#true
# print(str1.startswith("a"))#false
# 12.判断字符串以什么结束：endswith()
# str1 = "day is monday"
# print(str1.endswith("day"))#true
# print(str1.endswith("ay"))#true
# 应用常见：判断文件是否以.txt结尾
# file_name = input("输入文件名称")
# if file_name.endswith(".txt"):
# print("输入正确")
# else:
# print("输入错误")
# 13.字符串查询，结果显示下标，都是正向索引
# ①从左边开始查:find()结果显示下标
# str1 = "come on"
# print(str1.find("o"))#1
#②从右边开始查：rfind()
# str1 = "come on"
# print(str1.rfind("e"))#3
# ③查询第二个同类型的字符
# str1 = "come on"
# print(str1.find("o",2))#5数字2（正向索引）代表从第几个开始查
# 14.替换字符串：replace()
# replace(substring,newstring,max)=====replace(旧字符，新字符，替换次数）
# str1 = "python easy"
# print(str1.replace("p","a"))#aython easy
# print(str1.replace("y","a"))#pathon easa 不写次数默认替换全部
# print(str1.replace("y","a",1))#pathon easa 替换1次
#15.将字符串所有大写字符转换为小写:lower()
# str1 = "PythOn eAsy"
# print(str1.lower())#python easy
#16.将字符串所有小写字符转换为大写：upper()
# str1 = "python easy"
# print(str1.upper())#PYTHON EASY
#17.判断字符串是否全部为数字 : isdigit=====>布尔值
# str1 = "1234d"
# print(str1.isdigit())#false
#18.判断字符串是否全部为字母 ： isalpha()
# str1 = "aaade"
# print(str1.isalpha())#true
#19.判断字符串是否全部为字母、数字或者字母数字组合：isalnum()
# str1 = "wdwc21"
# print(str1.isalnum())#true
# str1 = "wdw&%21"
# print(str1.isalnum())#false特殊字符为否
#20.判断字符串首字母是否为大写，其他是否为小写：istitle()
# str1 = "SDHDWH"
# print(str1.istitle())#false其他不为小写则为否
# str1 = "Sbccwcbw"
# print(str1.istitle())#true
#21.判断字符串是否全部为大写 ：isupper()
# str1 = "DWHWICHW"
# print(str1.isupper())#true
#22.判断字符串是否全部为小写：islower()
# str1 = "sachc"
# print(str1.islower())#true
# print(str1.isupper())#false
#23.python 中的列表----定义列表
# ①第一种方式
# list1 = ["hello","good",1323]
# print(list1)#['hello', 'good', 1323]
#②第二种方式
# 使用list()函数可以把字符串转换成列表
# str1 = "big sun"
# list1 = list(str1)
# print(list1)#['b', 'i', 'g', ' ', 's', 'u', 'n']
#24.列表中常用的函数与方法
# ①索引赋值
# list1 = ["ni","hao",123]
# list1="hello"
# print(list1)#['hello', 'hao', 123]
#②切片赋值
# list1 = ["ni","hao",123]
# list1='good'
# print(list1)#['g', 'o', 'o', 'd', 123]
# ③在列表末尾添加元素：append()
# list1 = ["ni","hao",123]
# 添加字符串
# list1.append("good")
# print(list1)#['ni', 'hao', 123, 'good']
#添加整型int(）
# list1.append(998)
# print(list1)#['ni', 'hao', 123, 998]
#添加列表
# list1.append(["nice",779])
# print(list1)#['ni', 'hao', 123, ['nice', 779]]
#③在列表中随机添加元素：insert()
list1 = ["ni","hao",123]
#添加字符串
# list1.insert(2,"ya")
# print(list1)#['ni', 'hao', 'ya', 123]
#添加整型int()
# list1.insert(1,567)
# print(list1)#['ni', 567, 'hao', 123]
#添加列表
# list1.insert(0,["good",479])
# print(list1)#[['good', 479], 'ni', 'hao', 123]
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