将月份转换为在快速排序中使用的等效数字
本文关键字：数字 快速排序 转换 | 更新日期: 2023-09-27 17:58:13
我从外部文本文件中读取了一些月份到数组中，我需要将这些月份转换为一个数组，该数组包含与月份等效的值，例如January=1、February=2等。这样就可以通过Quicksort对它们进行排序。
public static void Main(string[] args)
{
//Read external files into arrays.
string[] Month = File.ReadLines(@"Month.txt").ToArray();
string[] Year = File.ReadLines(@"Year.txt").ToArray();
//Convert arrays from string to double to be used in sort.
double[] YearSort = Array.ConvertAll(Year, double.Parse);
int UserInput1;
//Create new array that will hold selected array to be used in sort.
double[] data = new double[1022];
//Prompt user to select action.
Console.WriteLine("Press 1 to Sort by month or 2 to sort by year.");
UserInput1 = Convert.ToInt32(Console.ReadLine());
if(UserInput1 == 1)
{
Array.Copy(Month,data,1022);
QuickSort(data);
for (int i = 0; i < 1022; i++)
Console.WriteLine(data[i]);
Console.WriteLine();
}
else if (UserInput1 == 2)
{
Array.Copy(YearSort,data,1022);
QuickSort(data);
for (int i = 0; i < 1022; i++)
Console.WriteLine(data[i]);
Console.WriteLine();
}
else
{
Console.WriteLine("Please try again and select a valid option");
}
}
static int MonthToDouble( string Month )
{
int NewMonth = 0;
switch(Month)
{
case "January":
case "january":
NewMonth = 1;
break;
case "February":
case "february":
NewMonth = 2;
break;
case "March":
case "march":
NewMonth = 3;
break;
case "April":
case "april":
NewMonth = 4;
break;
case "May":
case "may":
NewMonth = 5;
break;
case "June":
case "june":
NewMonth = 6;
break;
case "July":
case "july":
NewMonth = 7;
break;
case "August":
case "august":
NewMonth = 8;
break;
case "September":
case "september":
NewMonth = 9;
break;
case "October":
case "october":
NewMonth = 10;
break;
case "November":
case "november":
NewMonth = 11;
break;
case "December":
case "december":
NewMonth = 12;
break;
}
return NewMonth;
}
static string DoubleToMonth(double Month)
{
string NewMonth = "";
switch ((int)Month)
{
case 1:
NewMonth = "January";
break;
case 2:
NewMonth = "February";
break;
case 3:
NewMonth = "March";
break;
case 4:
NewMonth = "April";
break;
case 5:
NewMonth = "May";
break;
case 6:
NewMonth = "June";
break;
case 7:
NewMonth = "July";
break;
case 8:
NewMonth = "August";
break;
case 9:
NewMonth = "September";
break;
case 10:
NewMonth = "October";
break;
case 11:
NewMonth = "November";
break;
case 12:
NewMonth = "December";
break;
}
return NewMonth;
}
//QuickSort for double data values are in ascending order.
public static void QuickSort(double[] data)
{
Quick_Sort(data, 0, data.Length - 1);
}
public static void Quick_Sort(double[] data, int left, int right)
{
int i, j;
double pivot, temp;
i = left;
j = right;
pivot = data[(left + right) / 2];
do
{
while ((data[i] < pivot) && (i < right)) i++;
while ((pivot < data[j]) && (j > left)) j--;
if (i <= j)
{
temp = data[i];
data[i] = data[j];
data[j] = temp;
i++;
j--;
}
} while (i <= j);
if (left < j) Quick_Sort(data, left, j);
if (i < right) Quick_Sort(data, i, right);
}
}
DateTime对象的Month属性为您提供从1开始的月份的整数值，如您所需。因此，您可以使用DateTime.ParseExact()将字符串解析为完整的DateTime对象，然后获取Month属性：
int monthNumber = DateTime.ParseExact("January", "MMMM", CultureInfo.CurrentCulture).Month;
您只需要将"January"替换为月份字符串，并保留"MMMM"，即"月份的全名"的Custom Format String。
以上代码所做的只是简化您的MonthToDouble()方法，由于某些原因您甚至没有使用该方法（而且它应该返回double，而不是int）。与你的标题相反，你已经有了一种"将月份转换为数字当量"的方法，你只是没有使用它。
所以，我想你唯一缺少的就是替换这个：
Array.Copy(Month,data,1022);
QuickSort(data);
有了这个：
double[] monthsAsDoubles = new double[Month.Length];
for (int i = 0; i < monthsAsDoubles.Length; i++)
{
monthsAsDoubles[i] = MonthToDouble(Month[i]);
}
QuickSort(monthsAsDoubles);
还要将MonthToDouble()的返回值从int更改为double（如果需要，请强制转换）。
编辑：仔细想想，Quantic的答案更简单。我将把这个留在这里作为一个替代方案。
通过使用DateTimeFormatInfo.MonthNames属性以及不区分大小写的字符串比较，可以大大简化代码。这还有一个优点，即更容易移植，以便为月份名称使用不同的语言。
以下是一个片段：
using System;
using System.Globalization;
using System.Linq;
using System.Collections.Generic;
public class Test
{
public static void Main()
{
var InputMonths = new List<string> { "January","march","sepTEmber","smarch" };
var MonthNames = new DateTimeFormatInfo().MonthNames.ToList();
var InputMonthNumbers = new List<int>();
foreach (var m in InputMonths)
{
//Find index of the month name, ignoring case
//Note if the input month name is invalid, FindIndex will return 0
int month_num = 1 + MonthNames.FindIndex(name => name.Equals(m, StringComparison.OrdinalIgnoreCase));
if (month_num > 0)
{
InputMonthNumbers.Add(month_num);
}
}
foreach (var n in InputMonthNumbers)
{
Console.WriteLine(n.ToString());
}
}
}
输出：
1
3
9