When working with files, errors can occur for many reasons:<\/p>\n\n\n\n
\u2022 File does not exist
\u2022 No permission to access file
\u2022 Disk full
\u2022 Wrong file mode<\/p>\n\n\n\n
To prevent your program from crashing, Python provides exception handling<\/strong> using If an error happens, the program will not stop \u2014 it will show the error message instead.<\/p>\n\n\n\n Occurs when the file does not exist.<\/p>\n\n\n\n Occurs when you don\u2019t have permission to access the file.<\/p>\n\n\n\n Runs if no error occurs.<\/p>\n\n\n\n Runs no matter what (used for cleanup).<\/p>\n\n\n\n Using \u2022 Prevents program crashes \u2022 Use Error handling is an essential skill for building reliable and professional Python applications.<\/p>\n\n\ntry<\/code> and except<\/code>.<\/p>\n\n\n\nBASIC TRY-EXCEPT EXAMPLE<\/strong><\/h2>\n\n\n\n
try:
file = open(\"data.txt\", \"r\")
content = file.read()
print(content)
file.close()
except:
print(\"An error occurred while opening the file.\")<\/pre>\n\n\n\nHANDLING SPECIFIC FILE ERRORS<\/strong><\/h2>\n\n\n\n
1. FileNotFoundError<\/strong><\/h3>\n\n\n\n
try:
with open(\"data.txt\", \"r\") as file:
content = file.read()
except FileNotFoundError:
print(\"File not found. Please check the file name.\")<\/pre>\n\n\n\n2. PermissionError<\/strong><\/h3>\n\n\n\n
try:
with open(\"data.txt\", \"w\") as file:
file.write(\"Hello\")
except PermissionError:
print(\"You do not have permission to access this file.\")<\/pre>\n\n\n\n3. Handling Multiple Exceptions<\/strong><\/h3>\n\n\n\n
try:
with open(\"data.txt\", \"r\") as file:
content = file.read()
except FileNotFoundError:
print(\"File not found.\")
except PermissionError:
print(\"Permission denied.\")
except Exception as e:
print(\"Some other error occurred:\", e)<\/pre>\n\n\n\nUSING ELSE AND FINALLY<\/strong><\/h2>\n\n\n\n
Else Block<\/strong><\/h3>\n\n\n\n
Finally Block<\/strong><\/h3>\n\n\n\n
try:
file = open(\"data.txt\", \"r\")
except FileNotFoundError:
print(\"File not found.\")
else:
print(file.read())
file.close()
finally:
print(\"File operation completed.\")<\/pre>\n\n\n\nBEST PRACTICE: WITH + TRY<\/strong><\/h2>\n\n\n\n
try:
with open(\"data.txt\", \"r\") as file:
content = file.read()
print(content)
except FileNotFoundError:
print(\"File not found.\")
except Exception as e:
print(\"Error:\", e)<\/pre>\n\n\n\nwith<\/code> automatically closes the file even if an error occurs.<\/p>\n\n\n\nWHY ERROR HANDLING IS IMPORTANT<\/strong><\/h2>\n\n\n\n
\u2022 Makes your program professional
\u2022 Helps debug problems easily
\u2022 Improves user experience<\/p>\n\n\n\nKEY TAKEAWAYS<\/strong><\/h2>\n\n\n\n
try<\/code> and except<\/code> to handle file errors
\u2022 Handle specific exceptions when possible
\u2022 Use with<\/code> statement for safe file handling
\u2022 Use finally<\/code> for cleanup tasks<\/p>\n\n\n\n