Pythonoperator
This section mainly describes the Python operators. To give a simple example 4 +5 = 9 . In the example,4 and 5 are called operands , and "+" is called an operator.
The Python language supports the following types of operators:
- Arithmetic operators
- Compare (relational) operators
- Assignment operators
- logical operators
- Bitwise operators
- Member operators
- Identity operator
- Operator Precedence
Python arithmetic operators
The Python arithmetic operators are the same as those in high-level language C, C + +.
The following hypothetical variables: a=10,b=20:
operator |
Description |
Example |
+ |
Add-Two objects added |
A + B output result 30 |
- |
Minus-get negative numbers or one number minus the other |
-B Output Result-10 |
* |
Multiply by two number or return a string that is repeated several times |
A * b output result 200 |
/ |
Except-X divided by Y |
B/A Output Results 2 |
% |
Modulo-Returns the remainder of the division |
B% A output result 0 |
** |
Power-Returns the Y power of X |
A**b is 10 of 20, output 100000000000000000000 |
// |
Rounding-Returns the integer portion of the quotient ( rounded down ) |
9//2 output result 4, 9.0//2.0 output 4.0 |
Python comparison operators
The Python arithmetic operators are basically the same as those for high-level language C, C + +, but have more <> comparison operators.
The following assumes that the variable A is 10 and the variable B is 20:
operator |
Description |
Example |
== |
Equals-compares objects for equality |
(A = = B) returns FALSE. |
!= |
Not equal-compares two objects for unequal |
(A! = B) returns TRUE. |
<> |
Not equal-compares two objects for unequal |
(a <> B) returns True. This operator is similar to! =. |
> |
Greater than-returns whether x is greater than Y |
(A > B) returns FALSE. |
< |
Less-Returns whether x is less than Y. All comparison operators return 1 for true, and return 0 for false. This distinction is equivalent to the special variable true and false. |
(A < B) returns TRUE. |
>= |
Greater than or equal-returns whether X is greater than or equal to Y. |
(a >= B) returns FALSE. |
<= |
Less than or equal-returns whether X is less than or equal to Y. |
(a <= B) returns True. |
Python assignment operator
The following assumes that the variable A is 10 and the variable B is 20:
operator |
Description |
Example |
= |
Simple assignment operator |
c = A + B assigns the result of the operation of A + B to 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 |
C *= A is equivalent to C = c * A |
/= |
Division assignment operator |
C/= A is equivalent to C = c/a |
%= |
Modulo assignment operator |
C%= A is equivalent to C = c% A |
**= |
Power assignment operator |
C **= A is equivalent to C = c * * A |
//= |
Take the divisible assignment operator |
C//= A is equivalent to C = c//A |
Python bitwise operators
A bitwise operator computes a number as a binary. The bitwise algorithms in Python are as follows:
The variable a in the following table is 60,b 13 and the binary format is as follows:
a = 0011 1100b = 0000 1101-----------------a &b = 0000 1100a |b = 0011 1101a ^b = 0011 0001~a = 1100 0011
operator |
description |
instance |
& |
Bitwise-AND Operator: two values that participate in the operation, if two corresponding bits are 1, the The result of the bit is 1, otherwise 0 |
(A & B) output 12, binary interpretation: 0000 1100 |
| |
bitwise OR operator: As long as the corresponding two binary has one for 1 o'clock, the result bit is 1. |
(A | b) output 61, Binary interpretation: 0011 1101 |
^ |
bitwise XOR operator: When two corresponding binary differences, the result is 1 |
(a ^ b) Output 49, Binary interpretation: 0011 0001 |
~ |
bitwise inverse operator: each bits of the data is reversed, which turns 1 to 0 and 0 to 1. ~x similar to -x-1 |
(~a) output-61, Binary interpretation: 1100 0011, in the complement form of a signed binary number. |
<< |
left move operator: Each binary of the operand all shifts left several bits, by << to the right of the number specified the number of bits moved, high drop, low fill 0. |
A << 2 output result 240, binary interpretation: 1111 0000 |
>> |
Right-shift operator: ">>" left The operands of the edge are all shifted right by several bits, >> the right number specifies the number of bits to move |
a >> 2 output result 15, binary interpretation: 0000 1111 |
Python logical operators
The Python language supports logical operators, with the following assumption that the variable A is ten and B is 20:
operator |
Logical Expressions |
Description |
Example |
and |
X and Y |
Boolean "and"-if x is False,x and y returns FALSE, otherwise it returns the computed value of Y. |
(A and B) returns 20. |
Or |
X or Y |
Boolean "or"-if X is non-0, it returns the value of x, otherwise it returns the computed value of Y. |
(A or B) returns 10. |
Not |
Not X |
Boolean "Non"-returns False if X is True. If X is False, it returns TRUE. |
Not (A and B) returns False |
Python member operators
In addition to some of the above operators, Python also supports member operators, which contain a series of members, including strings, lists, or tuples.
operator |
Description |
Example |
Inch |
Returns False if the value found in the specified sequence returns True. |
x in the y sequence, if X returns True in the y sequence. |
Not in |
Returns True if no value is found in the specified sequence, otherwise False. |
X is not in the Y sequence if x does not return True in the y sequence. |
Python identity operator
The identity operator is used to compare the storage units of two objects
operator |
Description |
Example |
Is |
is to determine whether two identifiers are referenced from an object |
x is y, similar to ID (x) = = ID (y) , returns True if the same object is referenced, otherwise False |
is not |
Is does not determine whether two identifiers are referenced from different objects |
x is not y, similar to ID (a)! = ID (b). Returns True if the reference is not the same object, otherwise False is returned. |
Note: the ID () function is used to get the object memory address.
Python operator Precedence
The following table lists all the operators from highest to lowest priority:
operator |
Description |
** |
Index (highest priority) |
~ + - |
Bitwise flip, unary Plus and minus (the last two methods are called [email protected] and [email protected]) |
* / % // |
Multiply, divide, modulo, and divide |
+ - |
Addition subtraction |
>> << |
Shift right, left shift operator |
& |
Bit ' and ' |
^ | |
Bitwise operators |
<= < > >= |
Comparison operators |
<> = = = |
equals operator |
= %= /= //= -= += *= **= |
Assignment operators |
Is isn't |
Identity operator |
In No in |
Member operators |
Not and OR |
logical operators |
6, Python basic syntax-operator