#Three paradigms
1. One data, one field
2. As long as there is a primary key
3. Reduce duplication
What is #GIL
called: what is the use of the global interpreter lock cpython
: how to achieve multitasking in the case of a single core NB
:
change the interpreter lock jpython
process plus coroutine (personal suggestion)
The thread is implemented in other languages, and python calls
![] (images/4.png) #Deep
copy and shallow copy
#Deep copy
Copy the data of each layer recursively
#Shallow copy
Copy the data of the first layer
#Difference from
reference Reference: multiple variables point to the same memory address
Copy: generate a new address (immutable types will not generate, int, string, tuple)
#python basically if the copy method is provided, it is a shallow copy
#private_x
: single leading underscore, private properties or methods, from somemodule import * prohibit import, class objects and subclasses can access
__xx: double leading underscores, avoid naming conflicts with attributes in subclasses, cannot be externally Direct access (renamed so that it cannot be accessed)
__xx__: double underscores, magic objects or attributes in the user namespace. For example: __init__ , __ Do not invent such names
by yourself xx_: single trailing underscore to avoid conflicts with Python keywords #module
search path
sys.path #module
update
from imp import reload #The
difference between importing two modules
import **** This can be used as a reference
from **** import *** This can be used as a deep copy
