The document discusses file handling in Python. It explains that the open() function is key for working with files in Python and takes a filename and mode as parameters. It describes different modes for opening files, including 'r' for reading, 'a' for appending, and 'w' for writing. The document also covers getting file attributes after opening and the close() method for closing files.

1. Prof. Neeraj Bhargava
Vishal Dutt
Department of Computer Science, School of
Engineering & System Sciences
MDS University, Ajmer

2.  File handling is an important part of any web
application.
 Python has several functions for creating, reading,
updating, and deleting files.
 The key function for working with files in Python is
the open() function.
 The open() function takes two parameters; filename,
and mode.
File Handling

3. Modes for Opening a file
 "r" - Read - Default value. Opens a file for reading, error if
the file does not exist
 "a" - Append - Opens a file for appending, creates the file if
it does not exist
 "w" - Write - Opens a file for writing, creates the file if it
does not exist
 "x" - Create - Creates the specified file, returns an error if
the file exists

4.  you can specify if the file should be handled as binary
or text mode.
 "t" - Text - Default value. Text mode
 "b" - Binary - Binary mode (e.g. images)
Syntax
To open a file for reading it is enough to specify the name of
the file:
f = open("demofile.txt")
//OR
f = open("demofile.txt", "rt")
//here ‘r’ for read and ‘t’ for text are the default values, you do
not need to specify them.

5. The file Object Attributes
 Once a file is opened and you have one file object, you
can get various information related to that file.
1 file.closed
Returns true if file is closed, false otherwise.
2 file.mode
Returns access mode with which file was opened.
3 file.name
Returns name of the file.
4 file.softspace
Returns false if space explicitly required with print, true
otherwise.

6. Example
# Open a file
fo = open("foo.txt", "wb")
print "Name of the file: ", fo.name
print "Closed or not : ", fo.closed
print "Opening mode : ", fo.mode
print "Softspace flag : ", fo.softspace
Output
Name of the file: foo.txt
Closed or not : False
Opening mode : wb
Softspace flag : 0

7. The close() Method
 The close() method of a file object flushes any
unwritten information and closes the file object, after
which no more writing can be done.
 Python automatically closes a file when th e reference
object of a file is reassigned to another file. It is a good
practice to use the close() method to close a file.
Syntax:-
fileObject.close()

8. Example
# Open a file
fo = open("foo.txt", "wb")
print "Name of the file: ", fo.name
# Close opend file
fo.close()
#Output
Name of the file: foo.txt

9. Questions
 What is File Handling in Python?
 Explain the important modes for file opening with
their work.
 Write a python script to open and close the file.