current position:Home>[learning notes] Python exception handling try except...
[learning notes] Python exception handling try except...
2022-01-29 16:23:18 【Broken wind Bosco】
Let's start with the complete code for exception handling :
try:
# Code to try to execute
except Wrong type 1:
# For the type of error 1, Corresponding code handling
pass
except Wrong type 2:
# For the type of error 2, Corresponding code handling
pass
except Wrong type 3 :
# For the type of error 3, Corresponding code handling
pass
except Exception as result:
# Print error messages
print(result)
else:
# Code that will execute without exception
pass
finally:
# No matter whether there is any abnormality , Code that will execute
print(" No matter whether there is any abnormality , Code that will execute ")
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In certain circumstances , We can't completely define all errors, so we introduce Exception Handle
try:
num = int(input(" Please enter an integer :"))
print(num/num)
# except ZeroDivisionError:
# print(" Please enter a correct integer , Can't divide 0:")
# You can write exception handling methods for error types
except ValueError:
print(" Please enter a number , You cannot enter letters or Chinese characters ")
except Exception as result:
print(" Unknown error %s" % result)
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Exception handling
- The transmission of exceptions -- When function / Method perform Something unusual happened , Meeting Pass exception to function / Method Of Calling party
- If Pass to main program , still No exception handling , The program will be terminated
Tips
- In development , You can add the operation of catching exceptions in the main function
- Other functions called in the main function China , As long as there is an exception , Will be passed to the main function Exception trapping in
- So you don't have to be in the code , A large increase in Exception trapping , Keep the code clean
demand
- Defined function
demo1()
Prompts the user to enter an integer and returns - Defined function
demo2()
calldemo1
- Call in main program
demo2
def demo1():
return int(input(" Please enter an integer :"))
def demo2():
return demo1()
# Take advantage of the transitivity of exceptions , Catch exception in main program
try:
print(demo2())
except Exception as result:
print(" Unknown error %s" % result)
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Actively throw an exception
Actively throw an exception
- stay
Python
One is provided in Exception Exception class - At development time , If meet Specific business requirements , hope Throw an exception , Sure :
- Create a
Exception
The object of - Use
raise
keyword Throw out Exception object
- Create a
demand
- Definition
input_password
function , Prompt user for password - If the user enters the length < 8, Throw an exception
- If the user enters the length >= 8 , Return the password entered
def input_password():
# 1. Prompt user for password
pwd = input(" Please input a password :")
# 2. Determine password length >= 8, Return the password entered by the user
if len(pwd) >= 8:
return pwd
# 3. If < 8 Actively throw an exception
print(" Actively throw an exception ")
# 1> Create exception object - You can use the error message string as an argument
ex = Exception(" Insufficient password length ")
# 2> Throw an exception
raise ex
# Prompt user for password
try:
print(input_password())
except Exception as result:
print(result)
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author[Broken wind Bosco],Please bring the original link to reprint, thank you.
https://en.pythonmana.com/2022/01/202201291623158212.html
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