print()用于打印内容至屏幕print(“hello”)字符串需要用单引号’或双引号"包围a = “hello"b = ‘hello’如果字符串中有单引号时，需要用双引号包围a = “That’s why"字符串中有双引号时，用单引号包围a = ‘“你好”‘注释使用双引号包围’‘‘这里是注释’‘‘变量，用于接收一个值a = “hello” #此处的a就是一个变量判断变量类型print(type(变量名))从键盘接收字符串score = input(“请输入一个数字:")类型转换#类型(变量)score = int(score) #将字符型的数值转换为int类型条件判断if…else…if a == b: print(“相等”)else: print(“不相等”)if…elif…else…if name == “小吴”: print(“大美女”)elif name == “小王”: print(“大帅哥”)else: print(“丑八怪”)判断成绩#输入一个分数，大于90，优秀#小于90，大于等于80，良好#大于等于60，小于80，及格#小于是60，不及格score = int(input(“请输入你的成绩:”))if score >= 90: print(“优秀”)elif score < 90 and score >= 80: print(“良好”)elif score < 80 and score >= 60: print(“及格”)else: print(“不及格”)循环循环指重复的做一件事情，也叫遍历、迭代while循环用while循环，必须得有一个计数器count = 0 #计数器#循环就是在重复执行循环体里的代码while count < 10: print(“test”) count +=1 #每次循环都需要对计数器+1，不然会死循环else: #程序正常结束之后执行的 print(“什么时候执行我呢”)break，结束循count = 0while count < 3: name = input(“请输入一个名字：”) print(“你输入的名字是”, name) if name == ‘quit’: break #遇到break结束循环，后面的else也不会被执行 count += 1else: # print(“什么时候执行我呢”)continue，结束当前循环，进入下次循环count = 0while count < 5: if count == 2: count += 1 continue #当遇到count=2时，跳出当前循环，进入下一次循环。 print(“哈哈哈”) count += 1猜数字import randomnum = random.randint(1, 100)count = 0while count < 7: count +=1 guess = input(“请输入一个数字:”) guess = int(guess) if guess > num: print(“猜大了”) continue elif guess == num: print(“恭喜你，猜对了”) break else: print(“猜小了”) continueelse: print(“错误次数过多”)for循环import randomnum = random.randint(1, 100)count = 0for i in range(3): guess = input(“请输入一个数字:”) guess = int(guess) if guess > num: print(“猜大了”) elif guess == num: print(“恭喜你，猜对了”) break else: print(“猜小了”)print(“错误次数过多”)字符串格式化%s为字符串,%s可以接受各种类型的值，%d为整数,%f为小数，类型不匹配会报错，建议使用%s，如果想保留2位小数则写成%.2fimport datetimename = ‘小王’today = datetime.date.today()welcome1 = “%s，周末了，亲手为家人泡上一道茶吧。今天的日期是%s” % (name, today)print(welcome1)name2 = ‘小张’print(name + ‘爱’ + name2)words = ‘你的名字是%s，你的年龄是%s，你的分数是%s’% (name,28,17.3)words2 = ‘你的名字是%s，你的年龄是%d，你的分数是%.2f’% (name,28,17.3)print(words)print(words2)#如果参数比较少的时候可以使用占位符的方式sql = ‘insert into student (id, name, age, addr ,phone, sex, qq, email) values ’ \ ‘("%s”, “%s”, “%s”, “%s”, “%s”, “%s”, “%s”, “%s”);’#参数较多时使用format()方法sqls = ‘insert into student (id, name, age, addr, phone, sex, qq, email) values ’ \ ‘({id},{name},{age}.{phone},{addr},{sex},{qq},{email})‘sql3 = sql.format(id=1,name=‘小张’,age=18,sex=‘男’,phone=12345678,qq=12346,email=“123@qq.com”)print(sql3)