如何在java中比较字符串 [英] How to Compare strings in java

问题描述

我有一个程序，我在做的地方，当用户键入的心情，它会输出一个基于它的报价。我需要告诉程序

如果用户满意，然后输出此文本问题是，我不知道如何获取程序基于它来识别输入和输出文本...这里是我为代码到目前为止。

I have a program I'm making where when the user type in a mood, it will output a quote based on it. I need to tell the program
if the user is happy, then output this text The problem is, I don't know how to get the program to recognize the input and output the text based on it... here's what I have for code so far.

import java.util.Scanner;
public class modd {
    public static void main(String arrgs[]) {
        System.out.println("Enter your mood:");
        Scanner sc = new Scanner(System.in);
        String mood = sc.nextLine();

        if (sc = happy) {
            System.out.println("test");

            if (sc = sad) {
                System.out.println("I am sad");
            }
        }
    }
} 

推荐答案

首先，看起来你正在处理错误的变量 sc 。我想你要比较 mood 。

First of all, it looks like you are dealing with the wrong variable sc. I think you meant to compare mood.

在处理字符串时，总是使用。 equals（），而不是 == 。 == 比较引用，通常不可靠， .equals（）比较实际值。

When dealing with strings, always use .equals(), not ==. == compares the references, which is often unreliable, while .equals() compares the actual values.

这也是一个好的做法，将字符串转换为全大写或全小写。在这个例子中，我将使用小写的 .toLowerCase（）。 .equalsIgnoreCase（）也是关于任何案例问题的另一种快速方法。

It's also good practice to either convert your string to all uppercase or all lower case. I'll use lower case in this example with .toLowerCase(). .equalsIgnoreCase() is also another quick way around any case problems.

我还推荐一个 if-else语句，而不是第二个 if -statement 。您的代码将如下所示：

I'd also recommend an if-else-statement, not a second if-statement. Your code would look like this:

mood=mood.toLowerCase()

if (mood.equals("happy")) {
    System.out.println("test");
}

else if (mood.equals("sad")) {
    System.out.println("I am sad");

}

这些都是相当基本的java概念，推荐阅读更多关于其中一些。您可以在这里查看一些文档和/或其他问题：

These are all pretty basic java concepts, so I'd recommend reading more thoroughly about some of them. You can check out some of the documentation and/or other questions here:

• if-else语句


• 字符串


• Java String.equals vs. ==

• if-else statement
• Strings
• Java String.equals versus ==

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