How to Reference the Same Parameter Multiple Times in fmt.Sprintf Format Strings?

Referencing the Same Parameter Multiple Times in fmt.Sprintf Format Strings

In the given code snippet, you have a function that generates SQL commands to create tables using fmt.Sprintf. While the original approach is verbose, you desire a way to reference the v parameter only once for better string formatting.

According to the documentation for fmt.Sprintf:

In Printf, Sprintf, and Fprintf, the default behavior is for each formatting verb to format successive arguments passed in the call. However, the notation [n] immediately before the verb indicates that the nth one-indexed argument is to be formatted instead.

This means you can pass the v variable once and use the [n] notation to specify the argument index to be formatted. For example, your updated function can be:

func getTableCreationCommands(v string) string {
    return fmt.Sprintf(`
        CREATE TABLE share_%[1]v PARTITION OF share FOR VALUES IN (%[1]v);
        CREATE TABLE nearby_%[1]v PARTITION OF nearby FOR VALUES IN (%[1]v);
    `, v)
}

Here, %[1]v tells the formatter to use the first argument, which is v, twice.

To use this function:

import "fmt"

func main() {
    s := "X"
    fmt.Println(getTableCreationCommands(s))
}

Output:

CREATE TABLE share_X PARTITION OF share FOR VALUES IN (X);
CREATE TABLE nearby_X PARTITION OF nearby FOR VALUES IN (X);

This approach provides a cleaner and more concise way to format your SQL commands with multiple references to the same parameter.

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