[Learn Python from scratch_1.3] Understand basic operators

Arithmetic operators:

add	reduce	take	remove	Rounding	Take remainder	Exponentiation
+	-	*	/	//	%	**

# 加：
print(1 + 2)    # 3
# 减：
print(4 - 3)    # 1
# 乘：
print(2 * 5)    # 10
# 除：
print(6 / 5)    # 1.2
# 整除：
print(6 // 5)   # 1
# 取余：
print(6 % 5)    # 1
# 幂运算：
print(2 ** 3)   # 8

Notice:

Integer division operation, the result of integer division is rounded down;

Remainder operation, remainder = dividend - divisor * quotient.

print(5 // -2)  # -3    结果=-2.5，向下取整=-3
print(5 % -2)   # -1    结果=5 - (-2) * (-3)

Assignment operator:

equal	Wait...
=	+= ···

a = 10
b = c = d = 10
b, c, d, = 10, 20, 30
e = 5 + 5
e += 5  # +=、-=、*=、/=、//=、%=、**=

Extension: Quickly swap the values ​​of two variables

a, b = 10, 20
print(a, b)     # 10 20
a, b = b, a
print(a, b)     # 20 10

Comparison operators:

value comparison operator	equal	not equal to	more than the	greater or equal to	less than	less than or equal to
	==	!=	>	>=	<	<=

id comparison operator/identity operator Whether referencing the same object	IDs are equal	ids are not equal
	is	is not

a, b = 10, 10
print(id(a), id(b))  # 4336288272 4336288272
print(a == b)        # True
print(a is b)        # True
print(a is not b)    # False

lst1 = [1, 2, 3]
lst2 = [1, 2, 3]
print(id(lst1), id(lst2))   # 4425922752 4425946240
print(lst1 == lst2)         # True
print(lst1 is lst2)         # False
print(lst1 is not lst2)     # True

Boolean operators:

And (with)	or	No
and	or	not
Both values ​​are True Returns True, otherwise False	One of the two values ​​is True Returns True, otherwise False	Negate the result

member operator Is it in the specified sequence?	in sequence	not in sequence
	in	not in

print('h' in 'hello')       # True
print('a' not in 'hello')   # True

lst = [1, 2, 3]
print(1 in lst)         # True
print(1 not in lst)     # False

Bit operators:

 Convert a number to binary form, counting binary digits:

Bit AND	bit or	Bit XOR	bit negation	Bit shift left	Bit shift right
&	|	^	~	<<	>>
Both corresponding bits are 1, Return 1, Otherwise 0	The two corresponding bits have a 1, Return 1, Otherwise 0	The two corresponding bits are not the same, Return 1, Otherwise 0	Bitwise negation,	Shift binary bits left by specified number of digits	Shift a binary bit to the right by the specified number of digits

Operator precedence:

Arithmetic operators > Bitwise operators > Comparison operators > Boolean operators > Assignment operators