需要将char转换为小写并在Java中替换它[重复]

Question

所以我需要制作一个基本的收银机，它可以接受数组中的 5 件物品，上面有价格。不过，有些商品将包含 HST（税）。了解哪些项目有税哪些没有。用户将在输入美元金额之前或之后按 h 或 H。我已经让大部分程序正常工作，但我无法让我的代码识别大写 H 以将税款放入其中。 这是我的代码，任何信息都提前谢谢：

// Import scanner class
import java.util.Scanner;

 // Create class and method
class Main {
public static void main(String[] args) {

// Create scanner object and set scanner variables
Scanner inp = new Scanner(System.in);
System.out.println("Press any key to start");
String key = inp.nextLine();
System.out.println("\nEnter the amount of each item");
System.out.println("Upto 5 inputs are allowed!\n");

// Initialize counter and index variables to use it in the while loop
int counter = 0;
int index = 0;

// Create a double array variable, and set the limit to 5
double[] numbers = new double[5];

// Create a boolean variable to use it in the while loop
boolean go = true;

while(go) {           
    String value = inp.nextLine();      
    value.toLowerCase();
    // Set the index value to "h" or "H"
    int indexOfh = value.indexOf('h');
    
    boolean containsh = indexOfh == 0 || indexOfh == (value.length()-1);
    

    if(containsh){ //Validate h at beginning or end
        numbers[index] = Double.parseDouble(value.replace("h", ""));
        index++;
          System.out.println("HST will be taken account for this value");
    }
    counter++;
    if (counter == 5){
      go = false;
    }
}
System.out.println("HST Values:");

for(int i=0; i< numbers.length; i++) {
        System.out.println(numbers[i]);
}
}
}

Answer 1

我会完全删除indexOfh ：您可以将OR 一堆语句放在一起。这是安全的，因为 >= 是 evaluated before ||。

// Set the index value to "h" or "H"
boolean containsh = value.indexOf('h') >= 0
    || value.indexOf('H') >= 0;

此外，您可以通过使用startsWith 和endsWith 忽略中间的“H”或“h”来使您的要求更严格。

// Set the index value to "h" or "H"
boolean containsh = value.startsWith("h")
    || value.startsWith("H") || value.endsWith("h")
    || value.endsWith("H");

此外，由于您从不关闭Scanner，因此您有资源泄漏：您可以使用try-with-resources 让Java 为您管理它。这与其他一些简化一起产生了一个像这样的新版本。

// Import scanner class
import java.util.Scanner;

// Create class and method
public class so64283526 {
    public static void main(String[] args) {

        // Create scanner object and set scanner variables
        try (Scanner inp = new Scanner(System.in)) {
            System.out.println("Press any key to start");
            System.out.println("\nEnter the amount of each item");
            System.out.println("Upto 5 inputs are allowed!\n");

            // Initialize counter and index variables to use it in the while
            // loop
            int counter = 0;
            int index = 0;

            // Create a double array variable, and set the limit to 5
            double[] numbers = new double[5];

            while (counter++ < 5) {
                String value = inp.nextLine();
                value.toLowerCase();

                // Set the index value to "h" or "H"
                boolean containsh = value.startsWith("h")
                        || value.startsWith("H") || value.endsWith("h")
                        || value.endsWith("H");

                if (containsh) { // Validate h at beginning or end
                    numbers[index] = Double
                            .parseDouble(value.toLowerCase().replace("h", ""));
                    index++;
                    System.out.println(
                            "HST will be taken account for this value");
                }
            }
            System.out.println("HST Values:");

            for (int i = 0; i < numbers.length; i++) {
                System.out.println(numbers[i]);
            }
        }
    }
}

结果：

Press any key to start

Enter the amount of each item
Upto 5 inputs are allowed!

1
2H
HST will be taken account for this value
H3
HST will be taken account for this value
h4.7
HST will be taken account for this value
5.h6
HST Values:
2.0
3.0
4.7
0.0
0.0