Tutorial

Python io - BytesIO, StringIO

Published on August 3, 2022
author

Shubham

Python io - BytesIO, StringIO

Python io module allows us to manage the file-related input and output operations. The advantage of using the IO module is that the classes and functions available allows us to extend the functionality to enable writing to the Unicode data.

Python IO Module

There are many ways in which we can use the io module to perform stream and buffer operations in Python. We will demonstrate a lot of examples here to prove the point. Let’s get started.

Python BytesIO

Just like what we do with variables, data can be kept as bytes in an in-memory buffer when we use the io module’s Byte IO operations. Here is a sample program to demonstrate this:

import io

stream_str = io.BytesIO(b"JournalDev Python: \x00\x01")
print(stream_str.getvalue())

Let’s see the output for this program: python IO BytesIO example The getvalue() function just takes the value from the Buffer as a String.

Python StringIO

We can even use StringIO as well which is extremely similar in use to BytesIO. Here is a sample program:

import io

data = io.StringIO()
data.write('JournalDev: ')
print('Python.', file=data)

print(data.getvalue())

data.close()

Let’s see the output for this program: python StringIO example Notice that we even closed the buffer after we’re done with the buffer. This helps save buffer memory as they store data in-memory. Also, we used the print method with an optional argument to specify an IO stream of the variable, which is perfectly compatible with a print statement.

Reading using StringIO

Once we write some data to the StringIO buffer, we can read it as well. Let’s look at a code snippet:

import io

input = io.StringIO('This goes into the read buffer.')
print(input.read())

Let’s see the output for this program: python io module read stringIO data

Reading file using StringIO

It is also possible to read a file and stream it over a network as Bytes. The io module can be used to convert a media file like an image to be converted to bytes. Here is a sample program:

import io

file = io.open("whale.png", "rb", buffering = 0)
print(file.read())

Let’s see the output for this program: For this program to run, we had a whale.png image present in our current directory.

io.open() vs os.open()

The io.open() function is a much preferred way to perform I/O operations as it is made as a high-level interface to peform file I/O. It wraps the OS-level file descriptor in an object which we can use to access the file in a Pythonic way. The os.open() function takes care of the lower-level POSIX syscall. It takes input POSIX based arguments and returns a file descriptor which represents the opened file. It does not return a file object; the returned value will not have read() or write() functions. Overall, io.open() function is just a wrapper over os.open() function. The os.open() function just also sets default config like flags and mode too while io.open() doesn’t to it and depends on the values passed to it.

Conclusion

In this lesson, we studied simple operations of python IO module and how we can manage the Unicode characters with BytesIO as well. However, if you are looking for complete file operations such as delete and copy a file then read python read file. Reference: API Doc

Thanks for learning with the DigitalOcean Community. Check out our offerings for compute, storage, networking, and managed databases.

Learn more about our products

About the authors
Default avatar
Shubham

author

While we believe that this content benefits our community, we have not yet thoroughly reviewed it. If you have any suggestions for improvements, please let us know by clicking the “report an issue“ button at the bottom of the tutorial.

Still looking for an answer?

Ask a questionSearch for more help

Was this helpful?
 

Try DigitalOcean for free

Click below to sign up and get $200 of credit to try our products over 60 days!

Sign up

Join the Tech Talk
Success! Thank you! Please check your email for further details.

Please complete your information!

Become a contributor for community

Get paid to write technical tutorials and select a tech-focused charity to receive a matching donation.

DigitalOcean Documentation

Full documentation for every DigitalOcean product.

Resources for startups and SMBs

The Wave has everything you need to know about building a business, from raising funding to marketing your product.

Get our newsletter

Stay up to date by signing up for DigitalOcean’s Infrastructure as a Newsletter.

New accounts only. By submitting your email you agree to our Privacy Policy

The developer cloud

Scale up as you grow — whether you're running one virtual machine or ten thousand.

Get started for free

Sign up and get $200 in credit for your first 60 days with DigitalOcean.*

*This promotional offer applies to new accounts only.