This tutorial cover all file handling operations available in Python such as creating, reading, updating and deleting files.
open() function is used to open the file. It takes two parameters filename and mode. There are four different modes for opening a file.
- r – Read – Open a file for reading, throw an error if the file doesn’t exist. Default value
- w – Write – Open a file for writing. Create a file if the file doesn’t exist.
- a – append – Open a file for appending. Create the file if the file doesn’t exist.
- x – Create – Create the file, throw an error if the file exists
file = open('test.txt','r')
Let’s create a test.txt file in the same directory where your Python code is located. And copy the following content in the test.txt file.
Hello World! I am John Good Bye!
read() function is used to read the content of the file.
file = open('test.txt','r')
print(file.read())
readline() method is used to read a single line of the file.
file = open('test.txt','r')
print(file.readline()) # Output: Hello World!
print(file.readline()) # Output: I am John
Close Files
It is good practice to close the file using the close() method when you complete file operations.
file = open('test.txt','r')
print(file.readline())
file.close()
. . .
Write to File
To write to an existing file, you must add a parameter to the open() function:
- “a” – Append – will append to the end of the file
- “w” – Write – will overwrite any existing content
Example 1:
file = open('test.txt','a')
file.write("New line appended")
file.close()
#
file = open('test.txt','r')
print(file.read())
file.close()
This produces the following result:
Hello World! I am John Good Bye!New line appended
Example 2
file = open('test.txt','w')
file.write("Write new Line")
file.close()
#
file = open('test.txt','r')
print(file.read())
file.close()
This produces the following result:
Write new Line
. . .
Delete a File
To delete a file, you must import the OS module, and run its os.remove() function.
import os
os.remove("test.txt")
This line throws an error if the file doesn’t exist. So, it is better to check if file exists in the directory or not before using this function.
import os
if os.path.exists("test.txt"):
os.remove("test.txt")
else:
print("The file does not exist")
. . .