Explain the use of Go's blank identifiers for discarding values?

In Go, the blank identifier (written as underscore **_**) is a special identifier that can be used in place of any value of any type, but its value is discarded and not used. The blank identifier is often used when the value of an expression is not needed or is intentionally ignored.

One common use case of the blank identifier is when a function returns multiple values, but only some of them are needed. For example, consider the following function that returns two values:

func compute() (int, int) {
    return 1, 2
}

If we only need the second value and want to ignore the first one, we can use the blank identifier to discard it:

_, second := compute()

Here, we use the blank identifier to assign the first value to nothing, and assign the second value to the variable **second**.

Another use case of the blank identifier is to import a package solely for its side effects. In Go, a package's **init** function is executed automatically when the package is imported, even if no functions or variables are explicitly used from the package. This can be useful for initializing global state or registering a type's methods. However, if we only need the side effects and not the package's exported symbols, we can import the package with the blank identifier:

import _ "github.com/foo/bar"

Here, we use the blank identifier to import the package **github.com/foo/bar** for its side effects only, and not for its exported symbols.

In summary, the blank identifier is a special identifier in Go that can be used to discard the value of an expression or to import a package solely for its side effects. It is a useful feature that allows us to write more concise and expressive code in certain situations.