我有一个表示页面nos的字符串，如1,2,3,4,8,9,10,15。
我希望将它显示为1-4,8-10,15，即序列中的数字用连字符分隔，连字符由最小和最大数字依次包围。
如果按顺序中断，范围将用逗号分隔。
string pageNos = "5,6,7,9,10,11,12,15,16";
string result=string.Empty;
string[] arr1 = pageNos.Split(',');
int[] arr = new int[arr1.Length];
for (int x = 0; x < arr1.Length; x++) // Convert string array to integer array
{
arr[x] = Convert.ToInt32(arr1[x].ToString());
}
for (int i = 0; i < arr.Length;i++)
{
for (int j = i + 1; ; j++)
if (arr[i] == (arr[j] - 1))
result += arr[i].ToString() + "-" + arr[j].ToString();
else
result += arr[i].ToString() + ",";
}
Console.WriteLine(result);
答案 0 :(得分：8)
我认为循环内循环让事情变得更加混乱。尝试只使用一个循环，因为您只需要遍历整个列表一次。
int start,end; // track start and end
end = start = arr[0];
for (int i = 1; i < arr.Length; i++)
{
// as long as entries are consecutive, move end forward
if (arr[i] == (arr[i - 1] + 1))
{
end = arr[i];
}
else
{
// when no longer consecutive, add group to result
// depending on whether start=end (single item) or not
if (start == end)
result += start + ",";
else
result += start + "-" + end + ",";
start = end = arr[i];
}
}
// handle the final group
if (start == end)
result += start;
else
result += start + "-" + end;
答案 1 :(得分：4)
一点点LINQ会整理一下：
static IEnumerable<Tuple<int, int>> GetRanges(IEnumerable<int> source)
{
bool started = false;
int rangeStart = 0, lastItem = 0;
foreach (int item in source)
{
if (!started)
{
rangeStart = lastItem = item;
started = true;
}
else if (item == lastItem + 1)
{
lastItem = item;
}
else
{
yield return new Tuple<int, int>(rangeStart, lastItem);
rangeStart = lastItem = item;
}
}
if (started)
{
yield return new Tuple<int, int>(rangeStart, lastItem);
}
}
static string FormatRange(Tuple<int, int> range)
{
string format = (range.Item1 == range.Item2) ? "{0:D}" : "{0:D}-{1:D}";
return string.Format(format, range.Item1, range.Item2);
}
string pageNos = "5,6,7,9,10,11,12,15,16";
int[] pageNumbers = Array.ConvertAll(pageNos.Split(','), Convert.ToInt32);
string result = string.Join(",", GetRanges(pageNumbers).Select(FormatRange));
答案 2 :(得分：3)
string pageNos = "5,6,7,9,10,11,12,15,16";
string[] arr1 = pageNos.Split(',');
int[] arr = new int[arr1.Length];
for (int x = 0; x < arr1.Length; x++) // Convert string array to integer array
{
arr[x] = Convert.ToInt32(arr1[x]);
}
StringBuilder sb = new StringBuilder();
bool hyphenOpen = false;
for (int i = 0; i < arr.Length - 1; i++)
{
if (arr[i] + 1 == arr[i+1])
{
if (!hyphenOpen)
{
hyphenOpen = true;
sb.Append(arr[i] + "-");
}
}
else
{
hyphenOpen = false;
sb.Append(arr[i] + ",");
}
}
sb.Append(arr[arr.Length-1]);
Console.WriteLine(sb.ToString());
这很长而且很笨重，但它确实有效。
P.S。 - 我按原样离开了OP的原始字符串 - ＆gt; int，请参阅JonB关于更清晰方法的评论。
答案 3 :(得分：3)
您可以使用此方法获取相邻的数字组，其中每个组由自定义Range - 类表示：
class Range
{
public int? Start { get; set; }
public int? End { get; set; }
}
private static IEnumerable<Range> getAdjacentRanges(IEnumerable<int> nums)
{
var ranges = new List<Range>();
if (!nums.Any())
return ranges;
var ordered = nums.OrderBy(i => i);
int lowest = ordered.First();
int last = lowest;
ranges.Add(new Range { Start = lowest });
foreach (int current in ordered)
{
lastRange = ranges[ranges.Count - 1];
if (current > last + 1)
{
lastRange.End = last;
ranges.Add(new Range { Start = current });
}
last = current;
}
return ranges;
}
其余的很容易：
var arr = new[] { 1, 2, 3, 4, 8, 9, 10, 15 };
var ranges = getAdjacentRanges(arr)
.Select(r => r.End.HasValue ? string.Format("{0}-{1}", r.Start, r.End) : r.Start.ToString());
Console.Write(string.Join(",", ranges));
输出：1-4,8-10,15
答案 4 :(得分：2)
以下JS代码也有帮助
const givenArray = [1, 6, 6, 8, 44, 45, 47, 55, 9, 11, 12, 1, 6, 88, 13, 14, 2, 3, 5, 22, 33, 57, 88];
const input = [...new Set(givenArray)].sort((a, b) => a - b);
let i = 0;
let j = 0;
let output = '';
while (i < input.length) {
while (j < input.length && (input[j] + 1) === input[j + 1]) {
j++;
}
output += `${input[i]}`;
if (i !== j) {
output += ` - ${input[j]}, `;
} else {
output += ', ';
}
i = j + 1;
j = i;
}
console.log(output.substring(0, output.lastIndexOf(",")));
答案 5 :(得分：1)
我不是C＃的人，但我猜这里有问题：
if (arr[i] == (arr[j] - 1))
result += arr[i].ToString() + "-" + arr[j].ToString();
你不应该在结果中添加它。但设置一个标志（可能是布尔值），表示现在我开始计数了。
如果标志== ture且数字不再连续，那么就是添加到结果中的时间，当然是＆＃34; - ＆＃34;。
答案 6 :(得分：1)
这是一个不同的解决方案，它创建一个List<Tuple<int, int>>，其中包含每个非顺序值以及其后的连续值的数量。然后使用string.Join将其转换为字符串。
string pageNos = "1,2,3,4,8,9,10,15";
// Get list of numbers as ints
var list = pageNos.Split(',').Select(i => Convert.ToInt32(i)).ToList();
// Get a list of numbers and ranges of consecutive numbers
var ranges = new List<Tuple<int, int>>();
int start = 0;
for (int i = 0; i < list.Count; i++)
{
// First item always starts a new range
if (i == 0)
{
start = list[i];
}
// Last item always ends the current range
if (i == list.Count - 1)
{
if (list[i] == list[i - 1] + 1)
{
ranges.Add(new Tuple<int, int>(start, list[i] - start));
}
else
{
ranges.Add(new Tuple<int, int>(start, list[i - 1] - start));
ranges.Add(new Tuple<int, int>(list[i], 0));
}
}
// End the current range if nonsequential
if (i > 0 && i < list.Count - 1 && list[i] != list[i - 1] + 1)
{
ranges.Add(new Tuple<int, int>(start, list[i - 1] - start));
start = list[i];
}
}
// Craete the result string
var result = string.Join(", ", ranges.Select(r => r.Item2 == 0 ? r.Item1.ToString() : string.Format("{0}-{1}", r.Item1, r.Item1 + r.Item2)));
答案 7 :(得分：1)
public static string HyphenateRanges(this string input)
{
if (string.IsNullOrEmpty(input))
{
return "";
}
var orderedDistinct = input.Split(',')
.Select(Int32.Parse)
.Distinct()
.OrderBy(x => x)
.ToArray();
Func<int, int, string> replaceRangeValuesWithDash =
(x, i) =>
i == 0 || // first
i == orderedDistinct.Length - 1 || // last
orderedDistinct[i + 1] - orderedDistinct[i - 1] != 2 // not in a range
? x.ToString()
: "-";
var rangeValuesDashed = orderedDistinct
.Select(replaceRangeValuesWithDash)
.ToList();
var extraDashesRemoved = rangeValuesDashed
.Where((x, i) => i == 0 || rangeValuesDashed[i - 1] != x)
.ToArray();
var formattedString = String.Join(",", extraDashesRemoved)
.Replace(",-,", "-");
return formattedString;
}
答案 8 :(得分：1)
使用此助手类在数字列表和范围字符串之间来回转换。
这会复制来自here的ConvertNumberListToRangeString()和来自here的using System;
using System.Collections.Generic;
using System.Linq;
public static class NumberRangeHelper
{
/// <summary>
/// Converts a string of comma separated list of numbers and ranges to the list of individual numbers it represents.
/// </summary>
/// <param name="numbers">Range in form of <c>"2,4-8,11,15-22,39"</c></param>
/// <returns>A list of numbers</returns>
public static List<int> ConvertRangeStringToNumberList(string numbers)
{
var numbersSplit = numbers.Split(',');
var convertedNumbers = new SortedSet<int>();
foreach (var strNumber in numbersSplit)
{
int number;
if (int.TryParse(strNumber, out number))
{
convertedNumbers.Add(number);
}
else
{
// try and delimited by range
if (strNumber.Contains('-'))
{
var splitRange = strNumber.Split('-');
if (splitRange.Length == 2)
{
int firstNumber;
int secondNumber;
if (Int32.TryParse(splitRange[0], out firstNumber) &&
Int32.TryParse(splitRange[1], out secondNumber))
{
for (var i = firstNumber; i <= secondNumber; ++i)
{
convertedNumbers.Add(i);
}
}
}
}
}
}
return convertedNumbers.ToList();
}
/// <summary>
/// Converts a list of numbers to their concise range representation.
/// </summary>
/// <param name="numbers">A list of numbers such as <c>new[] { 1, 2, 3, 4, 5, 12, 13, 14, 19 }</c></param>
/// <returns>A string like <c>"1-5, 12-14, 19"</c></returns>
public static string ConvertNumberListToRangeString(IEnumerable<int> numbers)
{
var items = new SortedSet<int>(numbers)
.Select((n, i) => new { number = n, group = n - i })
.GroupBy(n => n.group)
.Select(g => (g.Count() >= 3)
? g.First().number + "-" + g.Last().number
: String.Join(", ", g.Select(x => x.number))
)
.ToList();
return String.Join(", ", items);
}
}
的实施，但略有改进。
Action<IEnumerable<int>> DumpList = l => Console.WriteLine("\t[{0}]", String.Join(", ", l));
Action<string> DumpRange = s => Console.WriteLine("\t\"{0}\"", s);
var numbers = new[] { 1, 1, 2, 3, 4, 5, 12, 13, 19, 19, 6, 7 };
DumpList(numbers);
var str = ConvertNumberListToRangeString(numbers);
DumpRange(str);
var list = ConvertRangeStringToNumberList(str);
DumpList(list);
Console.WriteLine();
str = "1-5, 12, 13, 19, 20, 21, 2-7";
DumpRange(str);
list = ConvertRangeStringToNumberList(str);
DumpList(list);
str = ConvertNumberListToRangeString(list);
DumpRange(str);
[1, 1, 2, 3, 4, 5, 12, 13, 19, 19, 6, 7]
"1-7, 12, 13, 19"
[1, 2, 3, 4, 5, 6, 7, 12, 13, 19]
"1-5, 12, 13, 19, 20, 21, 2-7"
[1, 2, 3, 4, 5, 6, 7, 12, 13, 19, 20, 21]
"1-7, 12, 13, 19-21"
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