How to Handle Missing Replacement Values in fmt.Sprintf?

Ignoring Surplus Fields in fmt.Sprintf

Consider a scenario where a Go program processes a string input from the command line and employs fmt.Sprintf to generate a formatted string. If the input, represented as tmp_str, contains placeholders (e.g., "%s") and the accompanying replacement value is not provided, fmt.Sprintf will raise an error with the message "EXTRA string=world," where "world" is the missing replacement.

To address this issue and gracefully handle situations where the input may lack placeholders, one approach is to require command-line users to consistently include a "%s" placeholder. This ensures that even when no value is assigned to the placeholder, the program avoids a panic. Truncating the string to zero length, as shown in the following example, will suppress any output associated with the placeholder:

<code class="go">package main

import "fmt"

func main() {
    tmp_str := "Hello Friends%.0s"
    str := fmt.Sprintf(tmp_str, "")
    fmt.Println(str)
}</code>

Output:

Hello Friends

By utilizing this strategy, the program can ignore any surplus replacement fields passed to fmt.Sprintf and maintain stable behavior.

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