Hello guys, welcome back to programminginpython.com! Here in this post, I will show you how to perform different File I/O operations like opening a file, reading content from the file, writing data to a file and all the stuff. You can do most of the operations I just mentioned by using a file object.
- Opening a file
- File Attributes
- Writing to a file
- Reading from a file
- Appending content to a file
- Deleting a file
Check this video on YouTube here.
Opening a file
If you want to perform any operations like reading, appending or writing, first, you must open a file. You can open a file by using a Python’s built in function open(). This open() function take 3 arguments, they are the file name, access mode and buffering.
some_file_object = open(file_name access_mode, buffering)
The 3 parameters,
file_name – This parameter contains the name of the file which you want to access or perform some operations on it.
access_mode – This access_mode determines in which mode the file should open, i.e reading(‘r‘), writing(‘w‘), appending(‘a‘), reading and writing(‘r+‘), reading in binary format(‘rb‘) and many other modes. Below is a list of all the access modes.
buffering – This buffering is an optional parameter if you want buffering option you set its value to 1, else 0 for no buffering, if you set it greater than 1, it will start buffering from that buffer size.
File Attributes
Once a file is opened, you can get the values of different attributes like the name of the file, mode of the file, whether the file is opened or closed.
file_attributes = open("test.txt", "wb")
print("Name of the file: ", file_attributes.name)
print("Closed or not : ", file_attributes.closed)
print("Opening mode : ", file_attributes.mode)
When you execute the above snippet, it produces the following output.
Writing to a file
For writing content to a file, you first need to open() it in writing mode, any of w, w+. `wb`, wb+ these modes can be used to write content to a file.
You can write either in binary format or normal text format. If you write in a binary format you need to convert the content to bytes.
file_write = open("test.txt", "wb")
file_write.write(bytes("Python is a great language.", 'UTF-8'))
file_write.close()
Without binary format,
file_write = open("test.txt", "w")
file_write.write("Python is a great language.")
file_write.close()
Both the above snippets create a new file if the file does not exist and if the file exists, it overwrites the content.
Reading from a file
For reading the content in a file, you need to open() the file, and then use the Python’s read() function to read the data.
# Open a file
file_read = open("test.txt", "r+")
text = file_read.read()
print("Read String is : ", text)
file_read.close()
You can open the file in any mode which supports reading a file.
Appending content to a file
When You need to add some extra content to the existing data, you should open the file in append mode, and do the rest as what you will do as in write mode. It is similar to write mode which I have shown in the above paragraphs, the main difference is the write mode overwrites the content but here the append mode adds to the existing content.
# Open a file
fo_append = open("test.txt", "a")
fo_append.write("\nPython is a powerful language.")
fo_append.close()
So now if I run the above snippet, it adds an extra line to the original content.
Delete a file
If you need to delete any file, then, in that case, you can use the Python’s built in function remove() to delete a file. However, you need to import the `os` module to do this and pass a file name you want to delete as an argument to remove() function.
import os
#delete a file
os.remove("test.txt")
That is how you can handle different file operations in Python. Below is the complete code snippet related to the file handling I/O operations covered above.
__author__ = 'Avinash'
import os
# Different file attributes
file_attributes = open("test.txt", "wb")
print("Name of the file: ", file_attributes.name)
print("Closed or not : ", file_attributes.closed)
print("Opening mode : ", file_attributes.mode)
file_attributes.close()
# Write to a file in binary format
file_write_bytes = open("test.txt", "wb")
file_write_bytes.write(bytes("Python is a great language.", 'UTF-8'))
file_write_bytes.close()
# Write to a file
file_write = open("test.txt", "w")
file_write.write("Python is a great language.")
file_write.close()
# Reading from a file
file_read = open("test.txt", "r+")
text = file_read.read()
print("Read String is : ", text)
file_read.close()
# Append to a file
file_append = open("test.txt", "a")
file_append .write("\nPython is a powerful language.")
file_append.close()
# Delete a file
os.remove("test.txt")
Also please feel free to check other posts on Python Lists, Python Tuples or Python GUI programming.