假设我有一个清单
var listOfInt = new List<int> {1,2,3,4,7,8,12,13,14}
如何使用LINQ获取列表列表,如下所示：
{{1,4},{7,8},{12,14}}
所以,我必须取连续值并将它们分组到列表中.
解决方法
您可以创建扩展方法(我省略了源检查),它将迭代源并创建连续项组.如果source中的下一项不连续,则会产生当前组：
public static IEnumerable<List<int>> ToConsecutiveGroups(
this IEnumerable<int> source)
{
using (var iterator = source.GetEnumerator())
{
if (!iterator.MoveNext())
{
yield break;
}
else
{
int current = iterator.Current;
List<int> group = new List<int> { current };
while (iterator.MoveNext())
{
int next = iterator.Current;
if (next < current || current + 1 < next)
{
yield return group;
group = new List<int>();
}
current = next;
group.Add(current);
}
if (group.Any())
yield return group;
}
}
}
用法很简单：
var listOfInt = new List<int> { 1,14 };
var groups = listOfInt.ToConsecutiveGroups();
结果：
[ [ 1,4 ],[ 7,8 ],[ 12,14 ] ]
更新：这是此扩展方法的通用版本,它接受谓词以验证是否应将两个值视为连续的：
public static IEnumerable<List<T>> ToConsecutiveGroups<T>(
this IEnumerable<T> source,Func<T,T,bool> isConsequtive)
{
using (var iterator = source.GetEnumerator())
{
if (!iterator.MoveNext())
{
yield break;
}
else
{
T current = iterator.Current;
List<T> group = new List<T> { current };
while (iterator.MoveNext())
{
T next = iterator.Current;
if (!isConsequtive(current,next))
{
yield return group;
group = new List<T>();
}
current = next;
group.Add(current);
}
if (group.Any())
yield return group;
}
}
}
用法很简单：
var result = listOfInt.ToConsecutiveGroups((x,y) => (x == y) || (x == y - 1));
