我正在尝试学习Java中的哈希映射和2D数组.我们有一个任务,因为有一个扫描仪接受一个字符串并将其转换为莫尔斯电码.我们使用的代码基于一个充满if语句的方法,但我想学习如何使用list,hashmaps或2D数组做这样的事情.我的代码如下：

import java.util.*;

public class MorseConversion

{

public static void main(String[] args)

{

Scanner userInput = new Scanner(System.in);

System.out.println("Please enter a phrase to convert to morse code: ");

String userString = userInput.nextLine();

System.out.println("");

System.out.println(stringConvert(userString));

}

public static String stringConvert(String userString)

{

String currentChar;

String getMorseChar;

String convertedString = "";

for (int i = 0; i < userString.length(); i++)

{

//Get character at i position

currentChar = userString.charAt(i) + "";

//convert character to morse code

getMorseChar = convert(currentChar);

//seperate words with the | symbol

if (getMorseChar.equals(" "))

{

convertedString = convertedString + " | ";

}

else

{

//concat the converted letter

convertedString = convertedString + getMorseChar;

//Add a space between each letter

if (!getMorseChar.equals(" "))

{

convertedString = convertedString + " ";

}

}

}

return convertedString;

}

public static String convert (String toEncode)

{

String morse = toEncode;

if (toEncode.equalsIgnoreCase("a"))

morse = ".-";

if (toEncode.equalsIgnoreCase("b"))

morse = "-...";

if (toEncode.equalsIgnoreCase("c"))

morse = "-.-.";

if (toEncode.equalsIgnoreCase("d"))

morse = "-..";

if (toEncode.equalsIgnoreCase("e"))

morse = ".";

if (toEncode.equalsIgnoreCase("f"))

morse = "..-.";

if (toEncode.equalsIgnoreCase("g"))

morse = "--.";

if (toEncode.equalsIgnoreCase("h"))

morse = "....";

if (toEncode.equalsIgnoreCase("i"))

morse = "..";

if (toEncode.equalsIgnoreCase("j"))

morse = ".---";

if (toEncode.equalsIgnoreCase("k"))

morse = "-.-";

if (toEncode.equalsIgnoreCase("l"))

morse = ".-..";

if (toEncode.equalsIgnoreCase("m"))

morse = "--";

if (toEncode.equalsIgnoreCase("n"))

morse = "-.";

if (toEncode.equalsIgnoreCase("o"))

morse = "---";

if (toEncode.equalsIgnoreCase("p"))

morse = ".--.";

if (toEncode.equalsIgnoreCase("q"))

morse = "--.-";

if (toEncode.equalsIgnoreCase("r"))

morse = ".-.";

if (toEncode.equalsIgnoreCase("s"))

morse = "...";

if (toEncode.equalsIgnoreCase("t"))

morse = "-";

if (toEncode.equalsIgnoreCase("u"))

morse = "..-";

if (toEncode.equalsIgnoreCase("v"))

morse = "...-";

if (toEncode.equalsIgnoreCase("w"))

morse = ".--";

if (toEncode.equalsIgnoreCase("x"))

morse = "-..-";

if (toEncode.equalsIgnoreCase("y"))

morse = "-.--";

if (toEncode.equalsIgnoreCase("z"))

morse = "--..";

if (toEncode.equalsIgnoreCase("0"))

morse = "-----";

if (toEncode.equalsIgnoreCase("1"))

morse = ".----";

if (toEncode.equalsIgnoreCase("2"))

morse = "..---";

if (toEncode.equalsIgnoreCase("3"))

morse = "...--";

if (toEncode.equalsIgnoreCase("4"))

morse = "....-";

if (toEncode.equalsIgnoreCase("5"))

morse = ".....";

if (toEncode.equalsIgnoreCase("6"))

morse = "-....";

if (toEncode.equalsIgnoreCase("7"))

morse = "--...";

if (toEncode.equalsIgnoreCase("8"))

morse = "---..";

if (toEncode.equalsIgnoreCase("9"))

morse = "----.";

if (toEncode.equalsIgnoreCase("."))

morse = ".-.-";

if (toEncode.equalsIgnoreCase(","))

morse = "--..--";

if (toEncode.equalsIgnoreCase("?"))

morse = "..--..";

return morse;

}

}

我出于好奇而严格地这样做.我已经把它砸到了我的脑海里,像这样的冗余是一个巨大的禁忌.提前致谢！

解决方法:

更简单的方法是使用初始化程序,使用字母作为键将字符加载到哈希映射中.然后,当您循环输入字符串中的字符时,您只需执行操作即可

在课程开始时做这样的事情：

private static HashMap codes = new HashMap();

static{

codes.put("a", ".-");

codes.put("b", "-...");

bla bla bla

}

然后在你的循环中

//convert character to morse code

getMorseChar = convert(currentChar);

你将会拥有

getMorseChar = code.get(currentChar.toLowerCase());

没有更讨厌的elseif声明.

标签：java,list,hashmap,encode

来源： https://codeday.me/bug/20190901/1781422.html