Скачать или смотреть How to Call a Go string-return Function from Python

Learn how to successfully call a Go string-return function from Python, resolve common issues, and improve compatibility between languages.
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Introduction

Have you ever tried to call a Go function from Python, only to be met with unexpected results? Many developers encounter challenges when integrating different programming languages, especially when it comes to handling string types. In this guide, we will explore how to call a Go function that returns a string in Python and address common issues that can arise during this process.

The Problem

When you call a Go function from Python, one common output issue is that it returns the string wrapped in bytes (for example, b'hello from go'). This can be confusing, especially if you expect to see just the string "hello from go". The difference in how Python 2 and Python 3 handle byte strings and regular strings adds complexity to this problem.

The Solution

To successfully call a Go function from Python and retrieve the true string value, follow these organized steps:

Understanding the Basics

What’s Happening Under the Hood?

Go strings are returned as *C.char, which is essentially a pointer to a C-style string.

Python interprets this C string as a bytes object.

In Python 2, bytes and str are the same, hence the confusion when switching to Python 3.

Converting Bytes to String

If you are using Python 3, you need to convert the returned bytes back to a proper string. Here’s how you can do that:

Modify Your Code: After calling the Go function, apply .decode('utf-8') to convert the bytes to a string.

Replace your print statement in your Python code from:

[[See Video to Reveal this Text or Code Snippet]]

to:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of .decode('utf-8'):

You are specifying that the bytes should be interpreted using UTF-8 encoding, which is the standard encoding used by Go.

Other C languages or libraries might use different encodings, so be careful to match the encoding to what the C library uses.

Example Code

Here’s a small example illustrating how to perform this operation correctly:

Go Code

Save this as a.go:

[[See Video to Reveal this Text or Code Snippet]]

Compile your Go code:

[[See Video to Reveal this Text or Code Snippet]]

Python Code

This is how your app.py script would look:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By following these steps, you can seamlessly call Go functions from Python and handle the returned string correctly. Always remember to decode the byte string when using Python 3 to ensure you're working with the proper string data type.

Final Thoughts

Integrating Go and Python can be a powerful way to harness the strengths of both languages. By understanding how they communicate and how to handle data types effectively, you can create more cohesive applications that leverage your programming expertise. Happy coding!