In Golang, the underscore (_) is a special identifier used as a placeholder. It has a few different use cases and can be quite handy once you understand its purposes.
One common use of the underscore in Golang is to ignore the value returned by a function or to indicate that a variable is not needed. For example, when using the range keyword to iterate over a collection, if you’re only interested in the index and not the value, you can use the underscore as a placeholder for the value:
for _, index := range mySlice {
// do something with the index
}
By using the underscore, you’re indicating to the compiler and other developers that you intentionally chose to ignore the value in this particular scenario.
Another use case for the underscore is when importing packages. Sometimes you might need to import a package solely for its side effects, such as initializing global variables or running init functions. In such cases, you can use the underscore to import the package without assigning it to a variable:
import _ "github.com/example/package"
By using the underscore, you’re telling the compiler that you’re importing the package for its side effects and not for direct use in your code. This can help make your code cleaner and more understandable.
It’s important to note that using the underscore as a variable name is not allowed by itself. It is a reserved identifier in Golang, and you’ll get a compile-time error if you try to use it as a regular variable.
Personal Thoughts and Commentary
In my experience with Golang, the underscore has proven to be quite useful in certain situations. It provides a clear indication to both the compiler and other developers that a value is intentionally being ignored or a package is being imported solely for its side effects. This can help improve the readability and maintainability of the code.
That being said, it’s important to use the underscore judiciously and only when it serves a clear purpose. Overusing the underscore can make the code harder to understand, especially for developers who are new to Golang.
Conclusion
The underscore (_) in Golang serves as a placeholder and has various use cases. It can be used to ignore the value returned by a function or to indicate that a variable is not needed. Additionally, it can be used when importing packages solely for their side effects. However, it is important to use the underscore judiciously and only when it serves a clear purpose in the code. By doing so, we can improve the readability and maintainability of our Golang code.