Python数据类型与运算符
数字类型
python提供了3种数字类型：整数（int）、浮点数（float）、复数（complex），常用的是整数和浮点数。
# 整数类型age=25big_number=9999999999999999999999999999999999999999print(f"年龄：{age}")print(type(big_number))# 浮点数----的精度问题result=0.1+0.2print(f"0.1 + 0.2 ={result}")print(f"结果是否等于0.3：{result==0.3}")# 复数complex_num1=3+4jcomplex_num2=complex(5,6)print(f"复数1：{complex_num1}")print(f"复数2：{complex_num2}")print(f"复数1的实部：{complex_num1.real}")print(f"复数1的实部：{complex_num1.imag}")字符串类型
# 字符串常用操作text=" Python Programming "print(f"原始字符串：'{text}'")print(f"去掉空格：'{text.strip()}'")print(f"转大写：'{text.upper()}'")print(f"转小写：'{text.lower()}'")print(f"替换内容：'{text.replace('Python','Java')}'")print(f"字符串长度：'{len(text)}'")print(f"是否包含Python：{'Python'intext}")#字符串索引和切片greeting="Hello, Python"print(f"第一个字符：{greeting[0]}")print(f"最后一个字符：{greeting[-1]}")print(f"前5个字符：{greeting[:5]}")print(f"后7个字符：{greeting[-7:]}")print(f"中间部分：{greeting[7:13]}")print(f"反转字符串：{greeting[::-1]}")布尔类型
# 布尔类型is_student=Trueis_working=False# 空值的布尔转换empty_string=""empty_list=[]zero=0print(f"空字符串的布尔值：{bool(empty_string)}")print(f"空列表的布尔值：{bool(empty_list)}")print(f"零的布尔值：{bool(zero)}")数据类型转换
# 字符串转数字str_num="123"int_num=int(str_num)float_num=float(str_num)print(f"字符串：{str_num}(类型：{type(str_num)})")print(f"整数：{int_num}(类型：{type(int_num)})")print(f"浮点数：{float_num}(类型：{type(float_num)})")# 数字转字符串number=456str_number=str(number)print(f"数字转字符串：{str_number}(类型：{type(str_number)})")实例应用场景
user_input=input("请输入一个数字：")try:number=int(user_input)result=number*2print(f"你输入的数字乘以2等于：{result}")exceptValueError:print("输入的不是有效数字！")算术运算符
# 基本算术运算a=10b=3print(f"加法：{a}+{b}={a+b}")print(f"减法：{a}-{b}={a-b}")print(f"乘法：{a}*{b}={a*b}")print(f"除法：{a}/{b}={a/b}")print(f"整除：{a}//{b}={a//b}")print(f"取摸：{a}%{b}={a%b}")print(f"幂运算：{a}**{b}={a**b}")# 实际应用：计算复利principal=1000# 本金rate=0.05# 年利率 5%time=3#3年compound_interest=principal*(rate+1)**time profit=compound_interest-principalprint(f"本金：{principal}元")print(f"年利率：{rate*100}%")print(f"时间：{time}元")print(f"复利后金额：{compound_interest:.2f}元")print(f"利润：{profit:.2f}元")比较运算符
# 比较与那算符示例x=10y=5print(f"{x}>{y}={x>y}")print(f"{x}<{y}={x<y}")print(f"{x}>={y}={x>=y}")print(f"{x}<={y}={x<=y}")print(f"{x}=={y}={x==y}")print(f"{x}!={y}={x!=y}")# 字符串比较name1="Alice"name2="Bob"print(f"字符串比较：{name1}<{name2}={name1<name2}")# 安字典序比较# 实际应用：成绩评级score=85ifscore>=90:grade="A"elifscore>=80:grade="B"elifscore>=70:grade="C"elifscore>=60:grade="D"else:grade="F"print(f"成绩：{score}分，等级：{grade}")逻辑运算符
# 逻辑运算符示例age=25has_job=Truehas_car=False# and运算符：所有条件都为True时结果才为Truecan_rent_car=age>=21andhas_jobprint(f"可以租车：{can_rent_car}")# or运算符：任意一个条件为True时结果才为Truecan_travel=has_carorage>=18print(f"可以旅行：{can_travel}")# not运算符：取反is_minor=not(age>=18)print(f"是未成年人：{is_minor}")# 复杂逻辑判断username="admin"password="123456"is_admin=username=="admin"andpassword=="123456"print(f"是管理员：{is_admin}")赋值运算符
# 基本赋值和复合赋值count=10print(f"初始值：{count}")count+=5print(f"加5后：{count}")count-=3print(f"减3后：{count}")count*=2print(f"乘2后：{count}")count//=4print(f"整除4后：{count}")# 实际应用：累加计算total=0numbers=[1,2,3,4,5]fornuminnumbers:total+=numprint(f"加入{num}后,总和为：{total}")print(f"最终总和：{total}")位运算符
# 位运算符示例a=12b=5print(f"a ={a}(二进制：{bin(a)})")print(f"b ={b}(二进制：{bin(b)})")print(f"b & b ={a&b}(按位与)")print(f"b | b ={a|b}(按位或)")print(f"b ^ b ={a^b}(按位异或)")print(f"~a ={~a}(按位取反)")print(f"a << 1 ={a<<1}(左移 1 位)")print(f"a >> 1 ={a>>1}(右移 1 位)")成员运算符和身份运算符
# 成员运算符fruits=["apple","banana","cherry"]print(f"apple在列表中:{'apple'infruits}")print(f"grape不在列表中:{'grape'notinfruits}")# 字符串中的成员运算text="hello，python"print(f"python在字符串中:{'python'intext}")# 身份运算符list1=[1,2,3]list2=[1,2,3]list3=list1print(f"list1 is list2:{list1islist2}")print(f"list1 is list3:{list1islist3}")print(f"list1 == list2:{list1==list3}")# 小整数对象的特殊情况x=100y=100print(f"x is y：{xisy}")#小整数有缓存