Python Learning Record (base-2)

Python built-in type

The main built-in types are numbers, sequences, mappings, classes, instances, and exceptions

Python Data Type Number

Integer integers: The operations performed are integers. Such as

>>>a = 10/3>>>a3

Long integers: Long integer is a superset of integral type. That is, a long integer can represent a larger number than an integral type. Python's long integer expression values are related to computer-supported (virtual) memory. For example

>>>a = 123456L

Float floating point Numbers: 8 bytes (64 bits) per floating-point type. Double-precision floating-point type. For large or very small floating-point numbers, it must be expressed in scientific notation, the 10 is replaced with E, 1.23x109 is 1.23e9 , or 12.3e8 , 0.000012 can be written as 1.2e-5 , and so on. Information about the precision of floating-point types and their internal characteristics in specific machines can be sys.float_info Obtained in .

>>> float ('+1.23')1.23>>> float ('   -12345\ n')-12345.0>>> float ('1e-003')0.001 >>> float ('+1E6')1000000.0>>> float (' -infinity ' )-inf

Complex Complex Numbers: A combination of a real number and an imaginary number forms a complex number. A complex number is a pair of ordered floating-point types (x, y), which is represented as the imaginary part of the Yj,yj. The imaginary numbers are now widely used in numerical and scientific computing applications.

A = 1 + 2j
#复数的内建属性
A.real   #实部
A.imag #虚部
A.conjugate () #共轭根式

Print (A.real)
Print (A.IMAG)
Print (A.conjugate ())

Operation Result:

1.0
2.0
(1-2J)

Process finished with exit code 0

Data operations

All numeric types (except complex numbers) are normal operations, and here I write several operators that are unique to Python. (Note: All operations have a higher priority than the comparison operation):

Floor except//: The decimal part of the result is removed, returning the nearest number in a sequence of numbers that is smaller than the true quotient.

x = 5= 2>>>x//y  2

A =-1
b = 2
>>>a//b
-1

Power Operation * *: Its execution priority is lower than the unary operator of its left operand, which has a higher precedence than the unary operator of its right-hand operand.

>>>9 * * 281>>>-9 * * 2-81>>> ( -9) * * 2  # brackets Increase Execution Priority 81>>>4.0 * *- 1.00.25

Bit arithmetic

Bitwise operations are only applicable to integer, Standard bitwise operations: ~ Negation, & with, | or, ^ XOR. The inventor of Python is also a mathematician, so there are many mathematical operators and it is convenient to use them. There is also left shift << and right shift >>.

Binary bitwise operations have lower precedence than numeric operations and are higher than comparison operations; unary operations ~ have the same precedence as other unary operations ( + and - ).

This table lists the bitwise operations arranged in ascending order:

Operation	Results
x | y	Bitwise or of X and Y
x ^ y	Bitwise XOR of X and Y
x ＆amp; y	The bitwise and of X and Y
x n	X left shift n bit
x >＆gt; n	X right shift n bit
~x	Invert each bit of X

#举个小栗子, you can try it on your own.

>>> A = 65
>>> b =46
>>> A & B
0
>>> A = 1
>>> B = 1
>>> A & B
1

On the left shift operation of binary, some problems of the original code complement are involved. I want to understand a bit more thoroughly, so leave a white here, later fill in:)

Python Learning Record (base-2)