如何在golang中交换字符串的子字符串？

Question

我正在尝试学习 Go-lang，因此在 Go 中使用字符串。但我无法正确交换字符串中的子字符串。

我的代码是：

package main

import (
    "fmt"
    "strings"
)

func main() {
    mystr := "I have an apple but not a mango, and she has a mango but not an apple"
    fmt.Println(mystr)
    mystr = strings.ReplaceAll(mystr, "apple", "(apple)")
    mystr = strings.ReplaceAll(mystr, "mango", "apple")
    mystr = strings.ReplaceAll(mystr, "(apple)", "mango")
    fmt.Println(mystr)
    mystr = strings.ReplaceAll(mystr, "an", "(a)")
    mystr = strings.ReplaceAll(mystr, "a", "an")
    mystr = strings.ReplaceAll(mystr, "(an)", "a")
    fmt.Println(mystr)
}

输出：

I have an apple but not a mango, and she has a mango but not an apple
I have an mango but not a apple, and she has a apple but not an mango
I hanve a mago but not an anpple, ad she hans an anpple but not a mago

有没有办法输入列表或字典（如在 python 中），这样我就可以定义交换并且不需要多次使用 strings.ReplaceAll()。

例如：

苹果 -> 芒果

芒果->苹果

一个->一个

一个->一个

期望的输出：

 I have a mango but not an apple, and she has an apple but not a mango

如果有多种方法可以做到这一点，我会很高兴了解每种方法的优缺点。

Answer 1

strings.ReplaceAll() 不执行“切换”，它只是将出现的 some 字符串替换为 another；但它不会执行用 some 替换 another。意思是ReplaceAll(s, "a", "b") 将用"b" 替换所有出现的"a"，但它不会用"a" 替换出现的"b"。

这是 2 次替换操作。而且这两个替换操作不能按顺序执行，因为一旦将“apple”替换为“mango”，您将只有“mango”，因此如果将“mango”替换为“apple” s，你只剩下“苹果”了。

相反，您可以使用strings.Replacer 列出多个可替换对，其Replacer.Replace() 方法将在一个步骤中执行所有替换。

还请注意，您不应将所有“a”替换为“an”，因为您的输入中可能还有其他“a”，而不仅仅是在“mango”之前。因此，最好将“an apple”替换为“a mango”，反之亦然。

s := "I have an apple but not a mango, and she has a mango but not an apple"
fmt.Println(s)

r := strings.NewReplacer("an apple", "a mango", "a mango", "an apple")
s = r.Replace(s)
fmt.Println(s)

输出（在Go Playground上试试）：

I have an apple but not a mango, and she has a mango but not an apple
I have a mango but not an apple, and she has an apple but not a mango