Python Basics Review-1-1 file types, variables, operators, expressions

File type: the

.py python源文件 由python解释器执行.pyc python源码编译后生成的文件（字节代码）编译方法：    源码文件中使用py_compile模块      import py_compile      py_complie.compile(‘***.py‘)      .pyo python源码优化编译后后文件    python -O -m compile ***.py  (无需要源码中使用 compile模块)    -O 表示优化    -m 表示模块    

Python variables

A variable is an area of computer memory that can store values within a specified range, and the value can be changed

The python under variable is a reference to a data

Variable

The python under variable is a reference to a data

Variable assignment is an area that points to a variable
Change the value of a variable to point to another area

Variable assignment does not need to declare a variable type, it automatically determines the type based on the value

Built-in functions

id()  内置函数 查看内存地址type() 内置函数  查看类型从键盘读取输入input("提示符")  字符串需用‘‘,适用于数字raw_input(“提示符”) 将所有输入做为字符串 建议使用

Assignment operators:

=   x = 2 将2赋于x+=  x += 2   <=>  x = x + 2-=  x -= 2   <=>  x = x - 2*=  x *= 2   <=>  x = x * 2/=  x /= 2   <=>  x = x / 2%=  x %= 2   <=>  x = x % 2  ```### 算术运算符：

• Connecting two number addition operations concatenate two strings, stitching strings
• Subtraction
• Multiplication
  /Division A number is a floating point and the result shows the number of decimal parts 4.0/3
  Divisible
  % take-up
  * * exponentiation

### 关系运算符：（返回值为布尔值 true fales）

Greater than
Less than
= greater than or equal to
<= less than or equal to
= = constant equals
! = does not equal

### 逻辑运算符

Add logic with True and False
or logical OR False or True
Not Logic not True

### 格式化字符串

%s
Print "%s +%s =%s"% (3, 4, 3+4)
Output:3 + 4 = 7
```

Python Basics Review-1-1 file types, variables, operators, expressions