Python3 operator
What is the operator?
This section mainly explained Python operators. Here is a simple example of 4 + 5 = 9. Example, 4 and 5 are called operands, "+" operator is called.
Python language supports the following types of operators:
- Arithmetic operators
- Comparison (relationship) operator
- Assignment Operators
- Logical Operators
- Bitwise Operators
- Member operator
- Identity operator
- Operator Precedence
Let one operator to learn Python.
Python Arithmetic Operators
The assumption that a variable is 10, the variable b is 21:
Operators | description | Examples |
---|---|---|
+ | Plus - two objects are added | a + b output 31 |
- | Save - get a negative number is subtracted from another number or | a - b Output -11 |
* | Multiply - multiply two numbers or returns the string repeated several times | a * b output 210 |
/ | In addition - x divided by y | b / a 2.1 output |
% | Modulo - returns the division remainder | b% a Output 1 |
** | Power - returns x raised to the power of y | a ** b 10 21 th |
// | Take divisible - Returns the integer part of quotient | 9 // 2 output 4, output 9.0 // 2.0 4.0 |
The following example demonstrates Python all arithmetic operators in action:
#!/usr/bin/python3 a = 21 b = 10 c = 0 c = a + b print ("1 - c 的值为:", c) c = a - b print ("2 - c 的值为:", c) c = a * b print ("3 - c 的值为:", c) c = a / b print ("4 - c 的值为:", c) c = a % b print ("5 - c 的值为:", c) # 修改变量 a 、b 、c a = 2 b = 3 c = a**b print ("6 - c 的值为:", c) a = 10 b = 5 c = a//b print ("7 - c 的值为:", c)
Examples of the above output:
1 - c 的值为: 31 2 - c 的值为: 11 3 - c 的值为: 210 4 - c 的值为: 2.1 5 - c 的值为: 1 6 - c 的值为: 8 7 - c 的值为: 2
Python comparison operators
The following assumptions variable a is 10, b is variable 20:
Operators | description | Examples |
---|---|---|
== | Equal - compare objects for equality | (A == b) returns False. |
! = | It is not equal - compare two objects are not equal | (A! = B) returns true. |
> | Greater than - Returns whether x is greater than y | (A> b) returns False. |
< | Less than - Returns whether x is less than y. All comparison operators return 1 for true and 0 for false. This respectively special variables True and False equivalence. Note that these variable name capitalization. | (A <b) returns true. |
> = | Greater than or equal - Returns whether x is greater than or equal y. | (A> = b) returns False. |
<= | Less than or equal - Returns whether x is less than or equal y. | (A <= b) returns true. |
The following example illustrates the comparison of all Python operations:
#!/usr/bin/python3 a = 21 b = 10 c = 0 if ( a == b ): print ("1 - a 等于 b") else: print ("1 - a 不等于 b") if ( a != b ): print ("2 - a 不等于 b") else: print ("2 - a 等于 b") if ( a < b ): print ("3 - a 小于 b") else: print ("3 - a 大于等于 b") if ( a > b ): print ("4 - a 大于 b") else: print ("4 - a 小于等于 b") # 修改变量 a 和 b 的值 a = 5; b = 20; if ( a <= b ): print ("5 - a 小于等于 b") else: print ("5 - a 大于 b") if ( b >= a ): print ("6 - b 大于等于 b") else: print ("6 - b 小于 b")
Examples of the above output:
1 - a 不等于 b 2 - a 不等于 b 3 - a 大于等于 b 4 - a 大于 b 5 - a 小于等于 b 6 - b 大于等于 b
Python assignment operator
The following assumptions variable a is 10, b is variable 20:
Operators | description | Examples |
---|---|---|
= | Simple assignment operator | c = a + b a + b operation will assign the result 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 | equivalent to c * = a 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 |
** = | Exponentiation assignment operator | c ** = a is equivalent to c = c ** a |
// = | Take divisible assignment operator | c // = a is equivalent to c = c // a |
The following example demonstrates the assignment operator of all Python operations:
#!/usr/bin/python3 a = 21 b = 10 c = 0 c = a + b print ("1 - c 的值为:", c) c += a print ("2 - c 的值为:", c) c *= a print ("3 - c 的值为:", c) c /= a print ("4 - c 的值为:", c) c = 2 c %= a print ("5 - c 的值为:", c) c **= a print ("6 - c 的值为:", c) c //= a print ("7 - c 的值为:", c)
Examples of the above output:
1 - c 的值为: 31 2 - c 的值为: 52 3 - c 的值为: 1092 4 - c 的值为: 52.0 5 - c 的值为: 2 6 - c 的值为: 2097152 7 - c 的值为: 99864
Python Bitwise Operators
Bitwise operators are considered binary numbers to make the calculation. Python is Bitwise rule as follows:
As a variable in the following table 60, b 13.
Operators | description | Examples |
---|---|---|
& | Bitwise and operator: two values involved in operation, if both corresponding bits are 1, the result bit is 1, 0 otherwise | (A & b) output 12, binary explanation: 0000 1100 |
| | Bitwise or operator: as long as the two corresponding binary bit is a 1, the resulting bit is 1. | (A | b) output 61, binary explanation: 00111101 |
^ | Bitwise exclusive OR operator: When the two corresponding binary bit different and the result is 1 | (A ^ b) the output of 49, binary explanation: 00110001 |
~ | Bitwise operators: each binary data bit inversion, that is 1 to 0, the 0 to 1 | (~ A) -61 output, binary explanation: 1100 0011 in a symbolic form complement binary number. |
<< | Left mobile operators: each binary operands all left a number of bits specified by the number "<<" right of the decimal moves, discarding the high and lower 0s. | a << 2 outputs 240 Binary interpretation: 11110000 |
>> | Right Mobile operators: to each binary ">>" the left operand Several all right, ">>" on the right the number of bits specified | a >> 2 output 15, binary explanation: 0000 1111 |
The following example demonstrates Python all bitwise operations:
#!/usr/bin/python3 a = 60 # 60 = 0011 1100 b = 13 # 13 = 0000 1101 c = 0 c = a & b; # 12 = 0000 1100 print ("1 - c 的值为:", c) c = a | b; # 61 = 0011 1101 print ("2 - c 的值为:", c) c = a ^ b; # 49 = 0011 0001 print ("3 - c 的值为:", c) c = ~a; # -61 = 1100 0011 print ("4 - c 的值为:", c) c = a << 2; # 240 = 1111 0000 print ("5 - c 的值为:", c) c = a >> 2; # 15 = 0000 1111 print ("6 - c 的值为:", c)
Examples of the above output:
1 - c 的值为: 12 2 - c 的值为: 61 3 - c 的值为: 49 4 - c 的值为: -61 5 - c 的值为: 240 6 - c 的值为: 15
Python logical operators
Python language supports logical operators, the assumption that a variable is 10, b 20:
Operators | Logical expression | description | Examples |
---|---|---|---|
and | x and y | Boolean "and" - if x is False, x and y returns False, else it returns evaluation of y. | (A and b) returns 20. |
or | x or y | Boolean "or" - If x is True, it returns True, else it returns evaluation of y. | (A or b) returns 10. |
not | not x | Boolean "not" - If x is True, it returns False. If x is False, it returns True. | not (a and b) returns False |
Examples of the above output:
#!/usr/bin/python3 a = 10 b = 20 if ( a and b ): print ("1 - 变量 a 和 b 都为 true") else: print ("1 - 变量 a 和 b 有一个不为 true") if ( a or b ): print ("2 - 变量 a 和 b 都为 true,或其中一个变量为 true") else: print ("2 - 变量 a 和 b 都不为 true") # 修改变量 a 的值 a = 0 if ( a and b ): print ("3 - 变量 a 和 b 都为 true") else: print ("3 - 变量 a 和 b 有一个不为 true") if ( a or b ): print ("4 - 变量 a 和 b 都为 true,或其中一个变量为 true") else: print ("4 - 变量 a 和 b 都不为 true") if not( a and b ): print ("5 - 变量 a 和 b 都为 false,或其中一个变量为 false") else: print ("5 - 变量 a 和 b 都为 true")
Examples of the above output:
1 - 变量 a 和 b 都为 true 2 - 变量 a 和 b 都为 true,或其中一个变量为 true 3 - 变量 a 和 b 有一个不为 true 4 - 变量 a 和 b 都为 true,或其中一个变量为 true 5 - 变量 a 和 b 都为 false,或其中一个变量为 false
Python member operator
In addition to some of the above operators, Python also supports member operator, test case contains a number of members, including strings, lists or tuples.
Operators | description | Examples |
---|---|---|
in | If you find the value in the specified sequence returns True, otherwise False. | x in y sequence, returns True if x in y sequence. |
not in | If the value is not found in the specified sequence returns True, otherwise False. | x is not y sequence, if x is not y sequence returns True. |
The following example demonstrates all the members of the Python operator actions:
#!/usr/bin/python3 a = 10 b = 20 list = [1, 2, 3, 4, 5 ]; if ( a in list ): print ("1 - 变量 a 在给定的列表中 list 中") else: print ("1 - 变量 a 不在给定的列表中 list 中") if ( b not in list ): print ("2 - 变量 b 不在给定的列表中 list 中") else: print ("2 - 变量 b 在给定的列表中 list 中") # 修改变量 a 的值 a = 2 if ( a in list ): print ("3 - 变量 a 在给定的列表中 list 中") else: print ("3 - 变量 a 不在给定的列表中 list 中")
Examples of the above output:
1 - 变量 a 不在给定的列表中 list 中 2 - 变量 b 不在给定的列表中 list 中 3 - 变量 a 在给定的列表中 list 中
Python identity operator
Identity operator is used to compare two objects of storage units
Operators | description | Examples |
---|---|---|
is | is judging the two identifiers are not referenced from an object | x is y, if id (x) equalsid (y), is returned 1 results |
is not | It is not to judge the two identifiers are not referenced from different objects | x is not y, if id (x) is not equal toid (y). is not returned 1 results |
The following example demonstrates the identity of all operators Python operations:
#!/usr/bin/python3 a = 20 b = 20 if ( a is b ): print ("1 - a 和 b 有相同的标识") else: print ("1 - a 和 b 没有相同的标识") if ( id(a) == id(b) ): print ("2 - a 和 b 有相同的标识") else: print ("2 - a 和 b 没有相同的标识") # 修改变量 b 的值 b = 30 if ( a is b ): print ("3 - a 和 b 有相同的标识") else: print ("3 - a 和 b 没有相同的标识") if ( a is not b ): print ("4 - a 和 b 没有相同的标识") else: print ("4 - a 和 b 有相同的标识")
Examples of the above output:
1 - a 和 b 有相同的标识 2 - a 和 b 有相同的标识 3 - a 和 b 没有相同的标识 4 - a 和 b 没有相同的标识
Python operator precedence
The following table lists from highest to lowest priority of all operators:
Operators | description |
---|---|
** | Index (highest priority) |
~ + - | Bitwise inversion, unary plus and minus (the last two method named + and @ - @) |
* /% // | Multiplication, division, and modulo take divisible |
+ - | Addition Subtraction |
>> << | Right, left operator |
& | Bit 'AND' |
^ | | Bitwise Operators |
<= <>> = | Comparison |
<> ==! = | Equality operator |
=% = / = @ = - = + = * = * = | Assignment Operators |
is is not | Identity operator |
in not in | Member operator |
not or and | Logical Operators |
The following example demonstrates all the Python operator precedence action:
#!/usr/bin/python3 a = 20 b = 10 c = 15 d = 5 e = 0 e = (a + b) * c / d #( 30 * 15 ) / 5 print ("(a + b) * c / d 运算结果为:", e) e = ((a + b) * c) / d # (30 * 15 ) / 5 print ("((a + b) * c) / d 运算结果为:", e) e = (a + b) * (c / d); # (30) * (15/5) print ("(a + b) * (c / d) 运算结果为:", e) e = a + (b * c) / d; # 20 + (150/5) print ("a + (b * c) / d 运算结果为:", e)
Examples of the above output:
(a + b) * c / d 运算结果为: 90.0 ((a + b) * c) / d 运算结果为: 90.0 (a + b) * (c / d) 运算结果为: 90.0 a + (b * c) / d 运算结果为: 50.0