Python operator.

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The operator

Operators are used to perform program code operations on more than one operand item.

For example: 2+3, the operands are 2 and 3, and the operator is +

Click the link below to jump to the corresponding knowledge points.

Arithmetic operator
Comparison operator
The assignment operator
Logical operator
An operator
Member operator
Identity operator
Python operator priority

IPython uses an introduction

IPython is a Python interactive Shell that is much easier to use than the default Python Shell. It supports automatic variable completion, automatic indentation, bash Shell commands, and many useful functions.

Here you’ll use the IPython interactive interpreter to test Python syntax.

The primary interface between a text operating system and the outside world is called the Shell. The Shell is the outermost layer of an operating system. The Shell manages your interaction with the operating system: waits for your input, interprets it to the operating system, and processes the output of various operating systems.

A Shell, commonly known as a Shell (to distinguish it from a core), is software that provides the user with a Command Interpreter, similar to CMD and PowerShell in Windows. It receives commands entered by the user and invokes the corresponding application.

The installation`IPython`

To install IPython, open CMD and enter the following command

pip install ipython
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The Package Installer for Python (PIP) is a Python package management tool that enables you to search for, download, install, and uninstall Python packages. When the Python interpreter is installed, it is configured for the user to use directly.

use`IPython`

To enter the ipython interpreter, use the Win + R shortcut keys to call up the run window and type ipython or enter ipython in the CMD window

Then enter the corresponding Python syntax to get the corresponding interpretation. The following presentation

advantages

Suitable for learning/validating Python syntax or local code

disadvantages

Code cannot be saved
Not suitable for running programs that are too large

Arithmetic operator

The operator	describe	The instance
`+`	add	3 + 6
`-`	Reduction of	Ten to five
*``**	take	*10 20**
`/`	In addition to	10/20
`//`	Take the divisible	Returns the integer part of the division (quotient)9 / / 2Output Result 4
`%`	modulo	Returns the remainder of the division9% 2
`支那`	power	Also known as power, power,*2 * 3**

IPython test

Addition and subtraction arithmetic operator tests

In [15] :# Addition

In [16]: a = 3

In [17]: b = 6

In [18]: c = a + b

In [19]: c
Out[19] :9

In [20]: a + b
Out[20] :9

In [21] :# subtraction

In [22]: a = 10

In [23]: b = 5

In [24]: a - b
Out[24] :5
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Multiplication and division arithmetic operator test

In [25] :# Multiplication

In [26]: a = 10

In [27]: b = 20

In [28]: a * b
Out[28] :200

In [29] :10 * 20
Out[29] :200
    
In [30] :# division

In [31] :10 / 20
Out[31] :0.5

In [32] :# take divisible

In [33] :10 / 3  # in addition to the ordinary
Out[33] :3.3333333333333335

In [34] :10 //3  # divisible
Out[34] :3    
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Tests for the mod and power arithmetic operators

In [35] :# modulo

In [36] :10 % 3
Out[36] :1

In [37] :# power operation

In [38] :2支那3
Out[38] :8

In [39] :2支那10
Out[39] :1024
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Comparison operator

Let’s say a is equal to 20, and b is equal to 30

The operator	describe	The instance
`= =`	Is equal to the	Return False
`! =`	Is not equal to	(a ! = b) returns True
`>`	Is greater than	A > b returns False
`<`	Less than	(a < b) returns True
`> =`	Greater than or equal to	(a >= b) returns False
`< =`	Less than or equal to	(a <= b) returns True

IPython test

Equal and unequal comparison operator tests

In [41] :# equals the comparison operator

In [42]: a = 20

In [43]: b = 30

In [44]: a == b
Out[44] :False

In [45] :# is not equal to

In [46]: a ! = b Out[46] :True
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Greater than and less than comparison operator tests

In [47] :# is greater than the

In [48]: a > b
Out[48] :False

In [49] :# is less than

In [50]: a < b
Out[50] :True
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Greater than or equal to, less than or equal to comparison operator tests

In [51] :# greater than or equal to

In [52]: a >= b
Out[52] :False

In [53] :Less than or equal to

In [54]: a <= b
Out[54] :True

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The assignment operator

The operator	describe	The instance
`=`	A simple assignment operator	C = a + b Assigns the result of a + b to c
`+ =`	The addition assignment operator	C plus a is the same thing as c is equal to c plus a
`- =`	The subtraction assignment operator	C minus a is the same thing as c minus a
*` =`**	Multiplication assignment operator	C times a is the same thing as c times a
`/ =`	The division assignment operator	C/a is the same thing as c = c/a
`/ / =`	Takes the divisible assignment operator	C //= a is equivalent to c = c // a
`% =`	takedie(remainder) assignment operator	C %= a is the same thing as c = c % a
*` * =`**	Power assignment operator	`c = a`Equivalent to `c = c a`

IPython test

Equal, plus, minus, and equal assignment operator tests

In [56] :# Assignment operator test

In [57] :# is equal to assignment

In [58]: a = 10

In [59]: b = 20

In [60]: c = a + b

In [61]: c
Out[61] :30

In [62] :# and equal

In [63]: a = 1

In [64]: a += 1

In [65]: a
Out[65] :2

In [66] :# is equal to the reduction

In [67]: a = 10

In [68]: a -= 1

In [69]: a
Out[69] :9
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Multiply equal, divide equal, and divide exactly assignment operator tests

In [70] :# take is equal to the

In [71]: a = 10

In [72]: a *= 5

In [73]: a
Out[73] :50

In [74] :# in addition to equal

In [75]: a = 100

In [76]: a /= 10

In [77]: a
Out[77] :10.0

In [78] :Take the divisible assignment operation

In [79]: a = 10

In [80]: a /= 3  # Ordinary division is equal to

In [81]: a
Out[81] :3.3333333333333335

In [84]: a = 10

In [85]: a //= 3  # take divisible

In [86]: a
Out[86] :3
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Take the remainder, power assignment operator test

In [87] :# take remainder assignment

In [88]: a = 10

In [89]: a %= 3

In [90]: a
Out[90] :1

In [91] :# Power assignment

In [92]: a = 2

In [93]: a **= 3

In [94]: a
Out[94] :8
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It’s an assignment based on an arithmetic operator

Logical operator

The operator	Logical expression	describe
`and`	`x and y`	Boolean “and”– beBoth sides of this expression are satisfiedDid not return to`True`, otherwise,`False`
`or`	`x or y`	Boolean “or”– Returns if one of the expressions is satisfied`True`Neither side is satisfied with talent`False`
`not`	`not x`	Boolean “not”– If x is True, return False. If x is False, it returns True.

andLogical operator IPython test

In [100] :# and logic operator test
In [101]: age = 21

In [102]: age > 18 and age < 30
Out[102] :True

In [103]: age > 30 and age < 18
Out[103] :False

In [108]: age < 18 and age == 21
Out[108] :False
 
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When using the and operator, the right-hand expression is not evaluated if the left-hand expression does not meet the criteria

In [115]: a = 21

In [116]: a > 18 and a == 1 / 0
---------------------------------------------------------------------------
ZeroDivisionError                         Traceback (most recent call last)
<ipython-input-116-9ea6c0ccc2d0> in <module>
----> 1 a > 18 and a == 1 / 0

ZeroDivisionError: division by zero

In [117]: a < 18 and a == 1 / 0
Out[117] :False
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So to prove this with a division by zero error message,

a = 21
a > 18 and a==1/0
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The Python interpreter reported an error in division by zero because a == 1/0.

a = 21
a < 18 and a==1/0
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First, the expression a < 18 does not satisfy the condition, because it is also the and operator, it does not perform the right a == 1/0 operation, so it does not give an error and False.

orLogical operator IPython test

In [118] :# or logical operator test
In [119]: score = 75

In [120]: score > 60 or socre < 80
Out[120] :True

In [121]: score > 60 or socre > 90
Out[121] :True

In [123]: score > 100 or score > 60
Out[123] :True

In [124]: score < 60 or score > 100
Out[124] :False
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When using the OR logical operator, the expression on the right is not evaluated if the expression on the left satisfies the condition

Again, divide by zero:

In [126]: score = 95

In [127]: score > 90 or score == score / 0
Out[127] :True

In [128]: score < 90 or score == score / 0
---------------------------------------------------------------------------
ZeroDivisionError                         Traceback (most recent call last)
<ipython-input-128-fd77ee8475bb> in <module>
----> 1 score < 90 or score == score / 0

ZeroDivisionError: division by zero

In [129] :Copy the code

notLogical operator IPython test

In [137]: a = 100

In [138]: a == 100
Out[138] :True

In [139]: a == 10
Out[139] :False

In [140] :not a == 100
Out[140] :False

In [141] :not a == 10
Out[141] :True
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The not operator is the opposite of an expression, False if it is True and True if it is not

An operator

Bitwise operators evaluate numbers as binary, and Python has the following table bit operators

The operator	describe
`&`	Bitwise andOperator: Two values involved in the operation, ifBoth corresponding bits are`1`, then the result of this bit is`1`, or for`0`
`\|`	Bitwise orOperator: as long as one of the two corresponding binaries is`1`, the result bit is`1`.
`^`	The bitwise exclusive orOperator: whenWhen two corresponding binaries differ, the result is 1
`~`	According to the notOperator: invert each binary bit of data, that is, change 1 to 0 and 0 to 1.~xSimilar to the-x-1
`<<`	Move the leftOperator: each binary of the operand moves several bits to the left. The number to the right of “<<” specifies the number of bits to move.Discard the high ones and fill the low ones with zeros.
`>>`	The rightOperator: Move all the binary bits of the operand to the left of “>>” several right, and the number to the right of “>>” specifies the number to move

IPython test

The default number we enter is base 10, so to make the test clearer, we use bin() to convert base 10 to base 2.

bin()Simple use of functions

In [6] :bin(10)
Out[6] :'0b1010'

In [7] :bin(8)
Out[7] :'0b1000'
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0b is binary

Bitwise and, bitwise or bitwise operator tests

In [0] :# bitwise and &
In [1] :bin(10)
Out[1] :'0b1010'

In [2] :bin(8)
Out[2] :'0b1000'

In [3]: a = 10

In [4]: b = 8

In [5]: a & b
Out[5] :8

In [6] :bin(a & b)
Out[6] :'0b1000'
    
In [7] :# or by location

In [8]: a | b
Out[8] :10

In [9] :bin(a | b)
Out[9] :'0b1010'
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Bitwise xor, bitwise inverse, bitwise operator test

In [10] :# bitwise xOR

In [11]: a = 10

In [12]: b = 8

In [13] :bin(a)
Out[13] :'0b1010'

In [14] :bin(b)
Out[14] :'0b1000'

In [15]: a ^ b
Out[15] :2

In [16] :bin(a ^ b)
Out[16] :'0b10'

In [17] :# reverse by bit

In [18]: a = 13

In [19] :bin(a)    # 0000, 1101,
Out[19] :'0b1101'

In [20] :bin(~a)   # 1111 1110 2-base complement with sign bits is rendered
Out[20] :'-0b1110'

In [21]: ~a
Out[21] : -14
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After bitwise inversion, as the form of binary complement is saved, it involves the knowledge points of binary origin, inversion and complement

Source code representation is the simplest representation of machine numbers. The highest bit is a sign bit. A sign bit of 0 means that the number is positive, and a sign bit of 1 means that the number is negative. For example, if [x] = 0000 0001, the decimal value is 1. If [x] = 1000 0001, the decimal value is -1.

Conversion skills of original, inverse and complement

Positive numbers have the same original and inverse complement

The complement of a negative number is equal to its inverse plus 1, the sign bit remains unchanged when the inverse is turned, and the rest are reversed by bits

The complement of a complement is the source code

So when a is equal to 13, there are eight bits representing a binary

13 Binary:0000, 1101,
13 If the digits are reversed:1111, 0010,, this isBinary complement with signed bits

Therefore, 1111 0010 complement code should be converted into the original code. Assuming that [x] complement code is 1111 0010, it can be concluded that the complement of the complement code is the original code

[x] =1111The original = 0010 [x]1000 1101 + 1  # 1 is decimal, replaced by 8-bit 2-base 0000 0001,2 base operation is 1 on every 2The original = [x]1000 1110
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[x] complement = 1111 0010 shows that [x] = 1000 1110, the sign bit is 1 is negative, so it is -14 in decimal. The result of derivation is in agreement with that of test.

Left move, right move, bit operator test

In [27] :# left < <
In [27]: a = 10

In [28] :bin(a)
Out[28] :'0b1010'    # 0000, 1010,

In [29] :bin(a << 2)
Out[29] :'0b101000'  # 0010, 1000,

In [30]: a << 2
Out[30] :40

In [31] :# moves to the right > >

In [32]: b = 7

In [33] :bin(7)		
Out[33] :'0b111'    # 0000, 0111,

In [34] :bin(b >> 2)
Out[34] :'0b1'      # 0000, 0001,

In [35]: b >> 2
Out[35] :1
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Member operator

The member operator tests whether a sequence contains a specified member

The operator	describe
`in`	Returns if a value is found in the specified sequence`True`Otherwise return`False`
`not in`	Returns if no value is found in the specified sequence`True`Otherwise return`False`

IPython test

In [37] :3 in (1.2.3)
Out[37] :True

In [38] :3 not in (1.2.3.4.5)
Out[38] :False

In [39] :0 not in (1.2.3)
Out[39] :True
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Identity operator

The operator	describe
`is`	Is determines whether two identifiers refer to an object
`is not`	Is not determines whether two identifiers refer to different objects

IPython test

In [40]: a = 20

In [41]: b = 20

In [42]: a is b
Out[42] :True

In [43]: a is not b
Out[43] :False

In [44]: a is not None
Out[44] :True
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Difference between is and == : IS is used to determine whether two variable reference objects are the same, and == is used to determine whether the values of reference variables are the same.

In [46]: a = [1.2.3]

In [47]: b = a

In [48]: a is b
Out[48] :True

In [49]: a == b
Out[49] :True

In [50]: c = [1.2.3]

In [51]: a is c
Out[51] :False

In [52]: a == c
Out[52] :True
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Python operator priority

The table below is listed in order of priority

The operator	describe
`支那`	Index (highest priority)
`~ + -`	Bitwise flip, unary plus and minus (the last two methods are called +@ and -@)
*`% / / /`**	Multiply, divide, find the remainder and take the exact division
`+ -`	Addition subtraction
`>> <<`	Shift right, shift left operator
`&`	Bitwise and operators
`^ \|`	Bitwise xor, bitwise or operators
`< = < > > =`	Comparison operator
`= =! =`	Equal operator
*`= %= /= //= -= += = =`	The assignment operator
`is is not`	Identity operator
`in not in`	Member operator
`not and or`	Logical operator

Operator priority, do not remember all, if you do not know the priority of the operation process can use () to increase the priority of the operator.

In [53]: a = 5

In [54]: b = 6

In [55]: c = 10

In [56]: a + b * c
Out[56] :65

In [57]: (a + b) * c
Out[57] :110
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The tail language

✍ Code writes the world and makes life more interesting. ❤ ️

✍ thousands of rivers and mountains always love, ✍ go again. ❤ ️

✍ code word is not easy, but also hope you heroes support. ❤ ️

Python operator.

The operator

Python operator.

IPython uses an introduction

The installationIPython

useIPython

Arithmetic operator

Comparison operator

The assignment operator

Logical operator

An operator

Member operator

Identity operator

Python operator priority

The tail language

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