python语法

1. 注释：

   ​
   # 单行注释
   
   """
   多行注释
   """
   
   ​

    

2. 变量

   name = "TOM"
   print(name)
   
   schoolName = "黑马"
   print(schoolName)

    

3. 数据类型

   # int
   num1 = 1
   print(type(num1))
   
   # float
   num2 = 1.1
   print(type(num2))
   
   # str
   a = 'hello world'
   print(type(a))
   
   # bool
   b = True
   print(type(b))
   
   # list 列表
   c = [1, 2, 3]
   print(type(c))
   
   # tuple 元组
   d = (10, 20, 30)
   print(type(d))
   
   # set 集合
   e = {1, 2, 3}
   print(type(e))
   
   # dict 字典
   f = {'name': 'TOM', 'age': 18}
   print(type(f))
   

    

4. 格式化输出

   age = 18
   name = 'TOM'
   weight = 75.5
   stu_id = 1
   stu_id2 = 1000
   
   # 1.今年我的年龄是x岁
   print('今年我的年龄是%d岁' % age)
   
   # 2.我的名字是x
   print('我的名字是%s' % name)
   
   # 3.我的体重是x公斤
   print('我的体重是%.2f公斤' % weight)
   
   # 4.我的学号是x
   print('我的学号是%d' % stu_id)
   
   # 4.1我的学号是001
   print('我的学号是%03d' % stu_id)
   print('我的学号是%03d' % stu_id2)
   
   # 5.我的名字是x,今年x岁了
   print('我的名字是%s,今年%d岁了' % (name, age))
   # 5.1我的名字是x,明年x岁了
   print('我的名字是%s,今年%d岁了' % (name, age + 1))
   
   # 6.我的名字是x,今年x岁了,体重是x公斤,学号是x
   print('我的名字是%s,今年%d岁了,体重是%.2f公斤,学号是%03d' % (name, age, weight, stu_id))
   
   # 语法f'{表达式}'
   print(f'我的名字是{name},明年{age + 1}岁了')
   

    

5. 转义字符

   print('hello\npython')
   print('\thello')
   print('world', end='\t')
   print('python', end='...')
   

    

6. 输入

   password = input('请输入您的密码:')
   print(f'您输入的密码是{password}')
   print(type(password))
   
   

    

7. 数据转换

   num = '1'
   print(type(int(num)))
   print(type(float(num)))
   
   num2 = 2
   print(type(str(num2)))
   
   list1 = [1, 2, 3]
   print(tuple(list1))
   
   tuple1 = (100, 200, 300)
   print(list(tuple1))
   
   str1 = '1'
   str2 = '1.1'
   str3 = '(1000,2000,3000)'
   str4 = '[1000,2000,3000]'
   print(type(eval(str1)))
   print(type(eval(str2)))
   print(type(eval(str3)))
   print(type(eval(str4)))
   

    

8. if语法

   if 2 > 1:
       print('2>1')
   
   age = 20
   if age < 18:
       print(f'您的年龄{age},童工')
   # elif (age >= 18) and (age <= 60):
   elif 18 <= age <= 60:
       print(f'您的年龄{age},合法')
   else:
       print(f'您的年龄{age},退休年龄')
   
   print("hello")
   

    

9. 随机数

   import random
   
   num = random.randint(0, 2)
   print(num)
   

    

10. 三目运算符

    a = 1
    b = 2
    c = a if a > b else b
    print(c)
    

     

11. 循环

    # while循环
    i = 0
    while i < 5:
        print('hello python')
        i += 1
        if i == 2:
            continue
        if i == 2:
            break
    
    # for循环
    str1 = 'python'
    for s in str1:
        if s == 't':
            continue
        if s == 'h':
            break
        print(s)
    
    # while else
    while i > 5:
        print(i)
    else:
        print(f'else->{i}')
    
    # for else
    for s in str1:
        print(s)
    else:
        print('for end')
    

     

12. 字符串

    str1 = 'hello'
    str2 = "python"
    desc = '''
    自动化运维
    自动化测试
    web开发
    爬虫
    机器学习
    数据分析
    人工智能
    '''
    desc2 = """
    hello python
    """
    print(desc)
    print(str1[1])