英文:
What does this particular line in java using indexOf mean?
问题
numbers[index] = Double.parseDouble(value.replace("h", ""));
这行代码的含义是：将输入的值去除首尾的字符 "h"，然后将剩余部分解析为一个双精度浮点数，并将其赋值给数组中指定索引位置的元素。
简单易懂的解释：
value是从用户输入中获取的字符串。value.replace("h", "")是将字符串中的所有 "h" 替换为空字符串，这样就去除了首尾可能存在的 "h"。Double.parseDouble(...)将经过处理的字符串转换为双精度浮点数。numbers[index]是一个数组，用于存储浮点数值。index是一个计数器，表示当前存储位置的索引。- 所以，这行代码的作用是将经过处理的浮点数值存储到数组中的指定位置。
例如，如果用户输入了 "3.5h"，经过处理后 "h" 被去除，剩下 "3.5" 被转换成浮点数，然后这个浮点数会被存储在 numbers 数组的特定位置，由 index 变量指示。
英文:
My Code:
// Import scanner classimport java.util.Scanner;// Create class and methodclass Main {public static void main(String[] args) {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");int counter = 0;int index = 0;double[] numbers = new double[5];boolean go = true;while(go) {String value = inp.nextLine();int indexOfH = value.indexOf("h");boolean containsH = indexOfH == 0 || indexOfH == (value.length()-1);if(containsH){ //Validate h at beginning or endnumbers[index] = Double.parseDouble(value.replace("h", ""));System.out.println("HST will be taken account for this value");}counter++;if (counter == 5){go = false;}}System.out.println("Printing Valid values");for(int i=0; i< numbers.length; i++) {System.out.println(numbers[i]);}}}
What does this line in my code mean?: `numbers[index] = Double.parseDouble(value.replace("h", ""));
I am new to java arrays, so can you explain it in a simple and easy way?
`
答案1
得分: 2
int indexOfH = value.indexOf("h");boolean containsH = indexOfH == 0 || indexOfH == (value.length()-1);`indexOfH` 是字符串中找到 `"h"` 的字符位置。更清楚的表达可以是：int indexOfH = value.indexOf("h");boolean containsH = value.startsWith("h") || value.endsWith("h");显然，`h` 是一个标记。通过以下方式从 `value` 中去除标记：String numValue = value.replace("h", "");然后可以将其转换为双精度浮点数：numbers[index] = Double.parseDouble(numValue);（因此，`value` 可能包含 `"3.14h"` 或 `"h2.89"`。）另一个注意：`value.indexOf('h')` 更加合乎逻辑，因为现在是在查找单个字符的位置，而不是整个字符串。
英文:
int indexOfH = value.indexOf("h");boolean containsH = indexOfH == 0 || indexOfH == (value.length()-1);
indexOfH is the char position in the string where "h" is found.
More clear would have been:
int indexOfH = value.indexOf("h");boolean containsH = value.startsWith("h") || value.endsWith("h");
Evidently "h" was a marker.
The value is stripped by
String numValue = value.replace("h", "");
And can then be converted to a double:
numbers[index] = Double.parseDouble(numValue);
(So value might have contained "3.14h" or "h2.89".)
An other note: value.indexOf('h') would have been more logical, as now the position of a char instead of an entire String is sought.
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