learning target:
算术运算符比较（关系）运算符逻辑运算符赋值运算符运算符的优先级
Learning Content:
A) Arithmetic Operators
- Is a complete basic arithmetic symbols used for mathematical processing
| Operators | description | Examples |
|---|---|---|
| + | plus | 10 + 20 = 30 |
| - | Less | 10 - 20 = -10 |
| * | Multiply | 10 * 20 = 200 |
| / | except | 10 / 20 = 0.5 |
| // | Take divisible | (Supplier) 2 9 // output portion 4 to return the integer division |
| % | Take the remainder | Returns the division remainder = 1 2 9% |
| ** | power | Also known as power, power, 2 3 = 8 ** |
- Results in Python string operators may also be used, the calculation results of the specified number of times the string is
B) Comparison (relationship) operator
| Operators | description |
|---|---|
| == | Check the value of the two operands if equal , if so, the condition is true, returns True |
| != | Check the value of the two operands if not equal , if so, the condition is true, returns True |
| > | Check whether the value of the left operand is greater than the value of the right operand, if so, the condition is true, returns True |
| < | Check the value of the left operand if less than the value of the right operand, if so, the condition is true, returns True |
| >= | Check whether the value of the left operand is greater than or equal to the value of the right operand, if so, the condition is true, returns True |
| <= | Check the value of the left operand if less than or equal to the value of the right operand, if so, the condition is true, returns True |
Python 2.x is judged not equal can also be used
<>operators
!=in Python 2.x likewise be used to determine not equal
C) logical operators
| Operators | Logical expression | description |
|---|---|---|
| and | x and y | Only the values of x and y are True, will return True or as long as x or y has a value of False, it returns False |
| or | x or y | As long as x or y has a value of True, it returns True only values of x and y are both False, will return False |
| not | not x | If x is True, it returns False if x is False, returns True |
Iv) assignment operator
- In python, you can assign values to variables using the =
- When the arithmetic operation, to simplify the code written, Python also provides a series of arithmetic operators corresponding to the assignment operator
- Note: the assignment operator can not use the intermediate spaces
| Operators | description | Examples |
|---|---|---|
| = | Simple assignment operator | c = a + b a + b is the assignment of the operation result c |
| += | Addition assignment operator | c + = a is equivalent to c = c + a |
| -= | Subtraction assignment operator | c - = a is equivalent to c = c - a |
| *= | Multiplication assignment operator | equivalent to c * = a c = c * a |
| /= | Division assignment operator | c / = a is equivalent to c = c / a |
| //= | Assignment operator take divisible | c // = a is equivalent to c = c // a |
| %= | Take modulus (remainder) assignment operator | c% = a is equivalent to c = c% a |
| **= | Power assignment operator | c ** = a is equivalent to c = c ** a |
E) operator precedence
- Arithmetic the priority table is arranged from high to low order
| Operators | description |
|---|---|
| ** | Power (highest priority) |
| * / % // | Multiply, divide, take the remainder, taking divisible |
| + - | Addition, subtraction |
| <= < > >= | Comparison Operators |
| == != | Equality operator |
| = %= /= //= -= += *= **= | Assignment Operators |
| not or and | Logical Operators |
Attention: Not supported in python increment and decrement (a ++, a -, ++ a, -a)
