How to write a dictionary to a file in Python?

General Discussions
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1

How do I write a dictionary to a text file in Python?

I have a dictionary and am trying to write it to a file.

exDict = {1: 1, 2: 2, 3: 3}
with open('file.txt', 'r') as file:
    file.write(exDict)

I got the error:

file.write(exDict)
TypeError: must be str, not dict

So I fixed the error like this:

exDict = {111: 111, 222: 222}
with open('file.txt', 'r') as file:
    file.write(str(exDict))

But then I got another error:

file.write(str(exDict))
io.UnsupportedOperation: not writable

How can I resolve this issue when trying to python write dict to file?

2

I’ve encountered this issue before, and it’s a simple fix! The error happens because the file is opened in read mode (‘r’), so you can’t write to it. To solve this, you need to open the file in write mode (‘w’). Here’s an example:

exDict = {1: 1, 2: 2, 3: 3}
with open('file.txt', 'w') as file:  # Open in write mode
    file.write(str(exDict))

This will resolve the io.UnsupportedOperation error and let you successfully write the dictionary to the file. It’s a straightforward way to handle your requirement for python write dict to file!

3

That’s a great start! But if you want to store your dictionary in a format that’s easier to read and retrieve later, using the json module is a better option. JSON provides a structured format, which is particularly useful for serializing and deserializing data. Here’s how you can implement it:

import json

exDict = {1: 1, 2: 2, 3: 3}
with open('file.txt', 'w') as file:
    json.dump(exDict, file)  # This writes the dictionary in JSON format

This approach is especially beneficial if you plan to parse the file later. It’s a great method to ensure that your data stays organized while addressing your need to python write dict to file. Plus, JSON is widely used, so it’s a good habit to adopt!

4

Another way to approach this, especially if you prefer a more human-readable format, is to write each dictionary entry on its own line. This can be handy for smaller dictionaries or when you want the file to be easily readable. Here’s how you can do it:

exDict = {1: 1, 2: 2, 3: 3}
with open('file.txt', 'w') as file:
    for key, value in exDict.items():
        file.write(f"{key}: {value}\n")  # Write each entry on a new line

This method outputs a neat format where each key-value pair appears on a separate line. It’s a simple and elegant way to handle python write dict to file, and it can be particularly helpful for debugging or quick lookups!