将字符串中的字符与字母进行比较? [英] Compare a character in a string with a letter?

问题描述

我想将字符串中的字符与字母"R"进行比较.因此，我想检查字符串中 i 位置上的字符是"R"，"L"还是"F".

I want to compare a character in a string with the letter "R". So I want to check if the character on the position i in the string is a "R", a "L" or a "F".

这是我的代码，但是没有字...我是Java的初学者，对于提高我的代码并使之起作用的每一个想法都很满意.

This is my code, but it doesn't word... I'm a Java beginner and really happy about every idea to improve my code and makes it work.

        for (int i = s.length()-2; i >= 0; i--){
            if (s.charAt(i) == "R"){
                    s = s + "L";}
            else if (s.charAt(i) == L){
                    s = s + "R";}
            else {s = s + "F";}

//s = s + s.charAt(i);}//对于

// s = s + s.charAt(i); }//for

顺便说一句，完整的练习是获得一个随机字符串(例如RFFLF)，添加一个R，然后以转后的顺序添加给定的字符串，并用L替换(在添加的字符串中)每个R和每个带有R的L.

By the way, the complete exercise is to get a random string (for example RFFLF), to add a R and then to add the given string in the turned around order and replace (in the added string) every R with L and every L with R.

推荐答案

首先，您必须小心自己的类型. s.charAt(i)返回一个 char 类型(鉴于方法的名称，这并不奇怪)，但是您正在将其与 String 进行比较.代码> "R" .那将无法编译，即使编译成功，也将无法正常工作.字符和字符串是不同的野兽，并且永远不相等.

First off, you must be careful with your types. s.charAt(i) returns a char type (not that surprising given the name of the method), but you're comparing it with a String "R". That won't compile and even if it did, it wouldn't work; chars and String are different beasts and are never equal.

char 文字由单引号分隔，例如'R'.

char literals are delimited by single quotes, eg 'R'.

此代码是我认为您要绑定的代码:

This code is what I think you're tying to code:

String result = "";
if (s.charAt(i) == 'R') {
    result = result + "L"; // you could code + 'L' too - both will work
}

请注意，您尝试修改原始String也不起作用.根据我的代码使用新的字符串.更容易理解和正确处理.

Note that your attempt at modifying the original String won't work either. Use a new String as per my code. Much easier to understand and get right.

这篇关于将字符串中的字符与字母进行比较?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！