Files
Files have 3 different parts -
- Header: metadata about the contents of the file (file name, size, type, and so on)
- Data: contents of the file as written by the creator or editor
- End of file (EOF): special character that indicates the end of the file
File Path is broken up in to 3 parts
*Folder Path: the file folder location on the file system where subsequent folders are separated by a forward slash / (Unix) or backslash \ (Windows)
- File Name: the actual name of the file
- Extension: the end of the file path pre-pended with a period (.) used to indicate the file type
line endings should use the sequence of the Carriage Return (CR or \r) and the Line Feed (LF or \n) characters (CR+LF or \r\n)
use open() to open a file. You should always properly close a file
reader = open('dog_breeds.txt')
try:
# Further file processing goes here
finally:
reader.close()
You can also use with. Automatically takes care of closing the file.
with open('dog_breeds.txt', r) as reader:
# Further file processing goes here
you’ll also want to use the second positional argument, mode.
ris for readwis for write
File Object - “an object exposing a file-oriented API (with methods such as read() or write()) to an underlying resource.”
Exceptions
Exceptions error - This type of error occurs whenever syntactically correct Python code results in an error. The last line of the message indicated what type of exception error you ran into.
use
raiseto throw an exception if a condition occurs. The statement can be complemented with a custom exception.
The
tryandexceptblock in Python is used to catch and handle exceptions
using the else statement, you can instruct a program to execute a certain block of code only in the absence of exceptions.
