How to Use strings.NewReader and strings.NewReplacer

Use strings.NewReader to create an io.Reader from a string and strings.NewReplacer to define find-and-replace pairs for efficient text substitution.

package main

import (
	"fmt"
	"strings"
)

func main() {
	// Create a reader from a string
	reader := strings.NewReader("Hello, World!")
	fmt.Printf("Reader: %s\n", reader.String())

	// Create a replacer with multiple pairs
	replacer := strings.NewReplacer("Hello", "Hi", "World", "Go")
	result := replacer.Replace("Hello, World!")
	fmt.Printf("Replaced: %s\n", result)
}

Use strings.NewReader when you need to treat a plain string as a stream of data, like reading from a file. Use strings.NewReplacer when you need to swap out multiple specific words or phrases in a text quickly. Think of the reader as turning text into a pipe and the replacer as a bulk find-and-replace tool.