Operators
Operator is a symbol that performs certain operations.
Python provides the following set of operators
1. Arithmetic Operators
2. Relational Operators or Comparison Operators
3. Logical operators
4. Bitwise oeprators
5. Assignment operators
6. Special operators
1. Arithmetic Operators:
+ ==>Addition
- ==>Subtraction
* ==>Multiplication
/ ==>Division operator
% ===>Modulo operator
// ==>Floor Division operator
** ==>Exponent operator or power operator
Eg: test.py:
1) a=10
2) b=2
3) print('a+b=',a+b)
4) print('a-b=',a-b)
5) print('a*b=',a*b)
6) print('a/b=',a/b)
7) print('a//b=',a//b)
8) print('a%b=',a%b)
9) print('a**b=',a**b)
Output:
1) Python test.py or py test.py
2) a+b= 12
3) a-b= 8
4) a*b= 20
5) a/b= 5.0
6) a//b= 5
7) a%b= 0
8) a**b= 100
Eg:
1) a = 10.5
2) b=2
3)
4) a+b= 12.5
5) a-b= 8.5
6) a*b= 21.0
7) a/b= 5.25
8) a//b= 5.0
9) a%b= 0.5
10) a**b= 110.25
Eg:
10/2==>5.0
10//2==>5
10.0/2===>5.0
10.0//2===>5.0
Note: / operator always performs floating point arithmetic. Hence it will always returns
float value.
But Floor division (//) can perform both floating point and integral arithmetic. If
arguments are int type then result is int type. If atleast one argument is float type then
result is float type.
Note:
We can use +,* operators for str type also.
If we want to use + operator for str type then compulsory both arguments should be str
type only otherwise we will get error.
1) >>> "Sohan"+10
2) TypeError: must be str, not int
3) >>> "Sohan"+"10"
4) 'Sohan10'
If we use * operator for str type then compulsory one argument should be int and other
argument should be str type.
2*"Sohan"
"Sohan"*2
2.5*"Sohan" ==>TypeError: can't multiply sequence by non-int of type 'float'
"Sohan"*"Sohan"==>TypeError: can't multiply sequence by non-int of type 'str'
+====>String concatenation operator
* ===>String multiplication operator
Note: For any number x,
x/0 and x%0 always raises "ZeroDivisionError"
10/0
10.0/0
.....
Relational Operators:
>,>=,<,<=
Eg 1:
1) a=10
2) b=20
3) print("a > b is ",a>b)
4) print("a >= b is ",a>=b)
5) print("a < b is ",a<b)
6) print("a <= b is ",a<=b)
7)
8) a > b is False
9) a >= b is False
10) a < b is True
11)
a <= b is True
We can apply relational operators for str types also
Eg 2:
1) a="Sohan"
2) b="Sohan"
3) print("a > b is ",a>b)
4) print("a >= b is ",a>=b)
5) print("a < b is ",a<b)
6) print("a <= b is ",a<=b)
7)
8) a > b is False
9) a >= b is True
10) a < b is False
11) a <= b is True
Eg:
1) print(True>True) False
2) print(True>=True) True
3) print(10 >True) True
4) print(False > True) False
5)
6) print(10>'Sohan')
7) TypeError: '>' not supported between instances of 'int' and 'str'
Eg:
1) a=10
2) b=20
3) if(a>b):
4) print("a is greater than b")
5) else:
6) print("a is not greater than b")
Output
a is not greater than b
Note: Chaining of relational operators is possible. In the chaining, if all comparisons
returns True then only result is True. If atleast one comparison returns False then the
result is False
Eg:
1) 10<20 ==>True
2) 10<20<30 ==>True
3) 10<20<30<40 ==>True
4) 10<20<30<40>50 ==>False
equality operators:
== , !=
We can apply these operators for any type even for incompatible types also
1) >>> 10==20
2) False
3) >>> 10!= 20
4) True
5) >>> 10==True
6) False
7) >>> False==False
8) True
9) >>> "Sohan"=="Sohan"
10) True
11) >>> 10=="Sohan"
12)
False
Note: Chaining concept is applicable for equality operators. If atleast one comparison
returns False then the result is False. otherwise the result is True.
Eg:
1) >>> 10==20==30==40
2) False
3) >>> 10==10==10==10
4) True
Logical Operators:
and, or ,not
We can apply for all types.
For boolean types behaviour:
and ==>If both arguments are True then only result is True
or ====>If atleast one arugemnt is True then result is True
not ==>complement
True and False ==>False
True or False ===>True
not False ==>True
For non-boolean types behaviour:
0 means False
non-zero means True
empty string is always treated as False
x and y:
==>if x is evaluates to false return x otherwise return y
Eg:
10 and 20
0 and 20
If first argument is zero then result is zero otherwise result is y
x or y:
If x evaluates to True then result is x otherwise result is y
10 or 20 ==> 10
0 or 20 ==> 20
not x:
If x is evalutates to False then result is True otherwise False
not 10 ==>False
not 0 ==>True
Eg:
1) "Sohan" and "Sohansoft" ==>Sohansoft
2) "" and "Sohan" ==>""
3) "Sohan" and "" ==>""
4) "" or "Sohan" ==>"Sohan"
5) "Sohan" or ""==>"Sohan"
6) not ""==>True
7) not "Sohan" ==>False
Bitwise Operators:
We can apply these operators bitwise.
These operators are applicable only for int and boolean types.
By mistake if we are trying to apply for any other type then we will get Error.
&,|,^,~,<<,>>
print(4&5) ==>valid
print(10.5 & 5.6) ==>
TypeError: unsupported operand type(s) for &: 'float' and 'float'
print(True & True) ==>valid
& ==> If both bits are 1 then only result is 1 otherwise result is 0
| ==> If atleast one bit is 1 then result is 1 otherwise result is 0
^ ==>If bits are different then only result is 1 otherwise result is 0
~ ==>bitwise complement operator
1==>0 & 0==>1
<< ==>Bitwise Left shift
>> ==>Bitwise Right Shift
print(4&5) ==>4
print(4|5) ==>5
print(4^5) ==>1
Operator
Description
&
If both bits are 1 then only result is 1 otherwise result is 0
|
If atleast one bit is 1 then result is 1 otherwise result is 0
^
If bits are different then only result is 1 otherwise result is 0
~
bitwise complement operator i.e 1 means 0 and 0 means 1
>>
Bitwise Left shift Operator
<<
Bitwise Right shift Operator
bitwise complement operator(~):
We have to apply complement for total bits.
Eg: print(~5) ==>-6
Note:
The most significant bit acts as sign bit. 0 value represents +ve number where as 1
represents -ve value.
positive numbers will be repesented directly in the memory where as -ve numbers will be
represented indirectly in 2's complement form.
Shift Operators:
<< Left shift operator
After shifting the empty cells we have to fill with zero
print(10<<2)==>40
>> Right Shift operator
After shifting the empty cells we have to fill with sign bit.( 0 for +ve and 1 for -ve)
print(10>>2) ==>2
We can apply bitwise operators for boolean types also
print(True & False) ==>False
print(True | False) ===>True
print(True ^ False) ==>True
print(~True)
==>-2
print(True<<2)
==>4
print(True>>2)
==>0
Assignment Operators:
We can use assignment operator to assign value to the variable.
Eg:
x=10
We can combine asignment operator with some other operator to form compound
assignment operator.
Eg: x+=10 ====> x = x+10
The following is the list of all possible compound assignment operators in Python
+=
-=
*=
/=
%=
//=
**=
&=
|=
^=
>>=
<<=
Eg:
1) x=10
2) x+=20
3) print(x) ==>30
Eg:
1) x=10
2) x&=5
3) print(x) ==>0
Ternary Operator:
Syntax:
x = firstValue if condition else secondValue
If condition is True then firstValue will be considered else secondValue will be considered.
Eg 1:
1) a,b=10,20
2) x=30 if a<b else 40
3) print(x) #30
Eg 2: Read two numbers from the keyboard and print minimum value
1) a=int(input("Enter First Number:"))
2) b=int(input("Enter Second Number:"))
3) min=a if a<b else b
4) print("Minimum Value:",min)
Output:
Enter First Number:10
Enter Second Number:30
Minimum Value: 10
Note: Nesting of ternary operator is possible.
Q. Program for minimum of 3 numbers
1) a=int(input("Enter First Number:"))
2) b=int(input("Enter Second Number:"))
3) c=int(input("Enter Third Number:"))
4) min=a if a<b and a<c else b if b<c else c
5) print("Minimum Value:",min)
Q. Program for maximum of 3 numbers
1) a=int(input("Enter First Number:"))
2) b=int(input("Enter Second Number:"))
3) c=int(input("Enter Third Number:"))
4) max=a if a>b and a>c else b if b>c else c
5) print("Maximum Value:",max)
Eg:
1) a=int(input("Enter First Number:"))
2) b=int(input("Enter Second Number:"))
3) print("Both numbers are equal" if a==b else "First Number is Less than Second Number" if
a<b else "First Number Greater than Second Number")
Special operators:
Python defines the following 2 special operators
1. Identity Operators
2. Membership operators
1. Identity Operators
We can use identity operators for address comparison.
2 identity operators are available
1. is
2. is not
r1 is r2 returns True if both r1 and r2 are pointing to the same object
r1 is not r2 returns True if both r1 and r2 are not pointing to the same object
Eg:
1) a=10
2) b=10
3) print(a is b) True
4) x=True
5) y=True
6) print( x is y) True
Eg:
1) a="Sohan"
2) b="Sohan"
3) print(id(a))
4) print(id(b))
5) print(a is b)
Eg:
1) list1=["one","two","three"]
2) list2=["one","two","three"]
3) print(id(list1))
4) print(id(list2))
5) print(list1 is list2) False
6) print(list1 is not list2) True
7)
print(list1 == list2) True
Note:
We can use is operator for address comparison where as == operator for content
Comparison.
2. Membership operators:
We can use Membership operators to check whether the given object present in the
given collection.(It may be String,List,Set,Tuple or Dict)
in è Returns True if the given object present in the specified Collection
not in è Retruns True if the given object not present in the specified Collection
Eg:
1) x="hello learning Python is very easy!!!"
2) print('h' in x) True
3) print('d' in x) False
4) print('d' not in x) True
5) print('Python' in x) True
Eg:
1) list1=["sunny","bunny","chinny","pinny"]
2) print("sunny" in list1) True
3) print("tunny" in list1) False
4) print("tunny" not in list1) True
Operator Precedence:
If multiple operators present then which operator will be evaluated first is decided by
operator precedence.
Eg:
print(3+10*2) è 23
print((3+10)*2) è 26
The following list describes operator precedence in Python
() è Parenthesis
** è exponential operator
~,- è Bitwise complement operator,unary minus operator
*,/,%,// è multiplication,division,modulo,floor division
+,- è addition,subtraction
<<,>> è Left and Right Shift
& è bitwise And
^ è Bitwise X-OR
| è Bitwise OR
>,>=,<,<=, ==, != ==>Relational or Comparison operators
=,+=,-=,*=... ==>Assignment operators
is , is not è Identity Operators
in , not in è Membership operators
not è Logical not
and è Logical and
or è Logical or
Eg:
1) a=30
2) b=20
3) c=10
4) d=5
5) print((a+b)*c/d) 100.0
6) print((a+b)*(c/d)) 100.0
7) print(a+(b*c)/d) 70.0
| Operator | Description |
|---|---|
| ** | Exponentiation (raise to the power) |
| ~ + - | Complement, unary plus and minus (method names for the last two are +@ and -@) |
| * / % // | Multiply, divide, modulo and floor division |
| + - | Addition and subtraction |
| >> << | Right and left bitwise shift |
| & | Bitwise 'AND'td> |
| ^ | | Bitwise exclusive `OR' and regular `OR' |
| <= < > >= | Comparison operators |
| <> == != | Equality operators |
| = %= /= //= -= += *= **= | Assignment operators |
| is is not | Identity operators |
| in not in | Membership operators |
| not or and | Logical operators |