Hướng dẫn python __exit__

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Tham khảo bài viết dưới đây để có ý tưởng về những điều cơ bản của người quản lý bối cảnh.

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Bàn luận
Trình quản lý bối cảnh được sử dụng để quản lý tài nguyên được sử dụng bởi chương trình. Sau khi hoàn thành việc sử dụng, chúng tôi phải phát hành bộ nhớ và chấm dứt các kết nối giữa các tệp. Nếu chúng không được phát hành thì nó sẽ dẫn đến rò rỉ tài nguyên và có thể khiến hệ thống chậm lại hoặc sụp đổ. Ngay cả khi chúng tôi không phát hành tài nguyên, các nhà quản lý ngữ cảnh hoàn toàn thực hiện nhiệm vụ này.

Tham khảo bài viết dưới đây để có ý tưởng về những điều cơ bản của người quản lý bối cảnh.

Quản lý bối cảnh

__exit __ () phương thức __exit__(self, exception_type, exception_value, exception_traceback)
Parameters:
Đây là một phương pháp của lớp bối cảnh. Phương pháp __exit__ quan tâm đến việc phát hành các tài nguyên bị chiếm giữ với đoạn mã hiện tại. Phương pháp này phải được thực thi bất kể điều gì sau khi chúng ta được thực hiện với các tài nguyên. Phương pháp này chứa các hướng dẫn để đóng đúng trình xử lý tài nguyên để tài nguyên được giải phóng để sử dụng thêm bởi các chương trình khác trong HĐH. Nếu một ngoại lệ được nâng lên; Loại, giá trị và dấu vết của nó được truyền dưới dạng đối số cho __exit __ (). Nếu không, ba không có đối số được cung cấp. Nếu ngoại lệ bị triệt tiêu, thì giá trị trả về từ phương thức __exit __ () sẽ đúng, nếu không, sai.indicates class of exception.
Cú pháp: __exit __ (self, exican_type, offic_value, exican_traceBack) & nbsp; indicates type of exception . like divide_by_zero error, floating_point_error, which are types of arithmetic exception.
Exception_Type: chỉ ra lớp ngoại lệ. & nbsp; traceback is a report which has all of the information needed to solve the exception.

Exception_Value: Cho biết loại ngoại lệ. Giống như lỗi Divide_by_zero, Floating_Point_error, là loại ngoại lệ số học. & NBSP;

Python3

Exception_TraceBack: Traceback là một báo cáo có tất cả thông tin cần thiết để giải quyết ngoại lệ.

# Ví dụ 1: & nbsp;

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

class ContextManager():

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

1class2

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

def __init__(______7

def

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

6self__

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

1ContextManager():5

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

ContextManager():7

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

1 1

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

class5 self

init method called
enter method called
with statement block
exit method called

def class9selfContextManager():1 Understanding parameters of __exit__(). We will create a context manager that will be used to divide two numbers. If the

Python3

Đầu ra

# Ví dụ 2: Hiểu các tham số của __exit __ (). Chúng tôi sẽ tạo một trình quản lý bối cảnh sẽ được sử dụng để chia hai số. Nếu & nbsp;

class 4

def __init__(self 9

class ContextManager():

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

1__init__(8

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

def __init__(______7

def

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

6self__

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

1):1

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

1):6):7

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

1 1 2

class5 self

def class9selfContextManager():1

Đầu ra

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Output:

Inside __enter__
3.0

Inside __exit__

Execution type: None

Execution value: None

Traceback: None
................................................
Inside __enter__

Inside __exit__

Execution type: 

Execution value: division by zero

Traceback: 
Traceback (most recent call last):
  File "gfg.py", line 32, in 
    r.divide_by_zero()
  File "gfg.py", line 21, in divide_by_zero
    print(self.num1 / self.num2)
ZeroDivisionError: division by zero

Hướng dẫn python __exit__ - python __exit__

Tham khảo bài viết dưới đây để có ý tưởng về những điều cơ bản của người quản lý bối cảnh.

Python3

Python3

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Hướng dẫn python exit - python exit