Bài trước: Python căn bản (9): Python Booleans
[Từ điển]
-----
10. Python Operators
10.1 Operators
Operators are used to
perform operations on variables and values.
In the example below,
we use the + operator to add together two values.
Example
print(10 + 5)
Python divides the operators in the following groups:
- Arithmetic operators
- Assignment operators
- Comparison operators
- Logical operators
- Identity operators
- Membership operators
- Bitwise operators
Python Arithmetic Operators
Arithmetic operators are used with numeric values to perform common
mathematical operations.
Operator Name Example
+ Addition x + y
- Subtraction x - y
* Multiplication x * y
/ Division x / y
% Modulus x % y
** Exponentiation x ** y
// Floor
division x // y
Python Assignment Operators
Assignment operators are used to assign values to variables.
Operator Example Same As
= x = 5 x = 5
+= x += 3 x = x + 3
-= x -= 3 x = x - 3
*= x *= 3 x = x * 3
/= x /= 3 x = x / 3
%= x %= 3 x = x % 3
//= x //= 3 x = x // 3
**= x **= 3 x = x ** 3
&= x &= 3 x = x & 3
|= x |= 3 x = x | 3
^= x ^= 3 x = x ^ 3
>>= x
>>= 3 x = x >> 3
<<= x
<<= 3 x = x << 3
:= print(x
:= 3) x = 3; print(x)
Python Comparison Operators
Comparison operators are used to compare two values.
Operator Name Example
== Equal x == y
!= Not equal x != y
> Greater
than x > y
< Less than x < y
>= Greater
than or equal to x >= y
<= Less than
or equal to x <= y
Python Logical Operators
Logical operators are used to combine conditional statements.
Operator Description Example
and Returns True if both
statements are true x < 5
and x < 10
or Returns True if one of
the statements is true x < 5 or x
< 4
not Reverse the result,
returns False if the result is true not(x
< 5 and x < 10)
Python Identity Operators
Identity operators are used to compare the objects, not if they are
equal, but if they are actually the same object, with the same memory location.
Operator Description Example
is Returns True if both
variables are the same object x is y
is not Returns True if both
variables are not the same object x
is not y
Example
x
=
["apple",
"banana"]
y
=
["apple",
"banana"]
z
=
x
print(x is z)
# returns True because z is the same
object as x
print(x is y)
# returns False because x is not
# the same object as y, even if they
have the same
Python Membership Operators
Membership operators are used to test if a sequence is presented in an
object.
Operator Description Example
in Returns True if a
sequence with the specified value is present in the object x in y
not in Returns True if a sequence
with the specified value is not present in the object x not in y
Example
x = ["apple", "banana"]
print("banana" in x)
# returns True because a sequence
with
# the value "banana" is in
the list
Python Bitwise Operators
Bitwise operators are used to compare (binary) numbers.
Operator Name Description Example
& AND Sets each bit to 1 if both bits are 1 x & y
| OR Sets each bit to 1 if one of two bits is 1 x | y
^ XOR Sets each bit to 1 if only one of two bits is
1 x ^ y
~ NOT Inverts all the bits ~x
<< Zero fill left
shift Shift left by pushing zeros in
from the right and let the leftmost bits fall off x << 2
>> Signed right shift Shift right by pushing copies of the
leftmost bit in from the left, and let the rightmost bits fall off x >> 2
Operator Precedence
Operator precedence describes the order in which operations are
performed.
Example
Parentheses have the highest precedence, meaning that expressions inside
parentheses must be evaluated first.
print((6 + 3) - (6 + 3))
Example
Multiplication * has higher precedence than addition +, and therefore
multiplications are evaluated before additions.
print(100 + 5 * 3)
The precedence order is described in the table below, starting with the
highest precedence at the top.
Operator Description
() Parentheses
** Exponentiation
+x -x ~x Unary
plus, unary minus, and bitwise NOT
* / // % Multiplication,
division, floor division, and modulus
+ - Addition
and subtraction
<< >> Bitwise
left and right shifts
& Bitwise
AND
^ Bitwise XOR
| Bitwise OR
== != > >= < <= is
is not in not in Comparisons,
identity, and membership operators
not Logical NOT
and AND
or OR
If two operators have the same precedence, the expression is evaluated
from left to right.
Example
Addition + and subtraction - has the same precedence, and therefore we
evaluate the expression from left to right.
print(5 + 4 - 7 + 3)
10. Exercise
1. What will be the result of the following code:
x = 5
x += 3
print(x)
A. 3
B. 5
C. 8
D. True
2. What will be the result of the following code:
print(2 * 0 == 2 and 2 ** 3 == 8)
A. True
B. 3
C. 8
D. False
3. What will be the result of the following code:
print(2 * 0 == 2 or 2 ** 3 == 8)
A. True
B. 3
C. 8
D. False
-----
The answer hints:
1(C), 2(D), 3(A)
-----
Cập nhật: 19/10/2024
Bài sau: Python căn bản (11): Python If ... Else
-----
[Nội dung tham khảo từ w3schools, pynative và Internet]
Bạn muốn học Python căn bản tại Đà Lạt, liên hệ