Check the grouping of values in List <string>
In one of my programs, I need to check the grouping of items in a list. So I have values in List<string>
. Here's an example of a list (in that order):
Women
's
Women
's Women 's Women 's
Women
's
Men
's
Men
's Men 's Men 's Women's
What I want to check is the grouping of this list. So the women downstairs shouldn't be there. This is the wrong grouping.
I CANNOT sort this list because there will be a special order for it, which is not simple as in the above list (and can have more than two different values) and always changes. However, grouping will be supported.
All I want to do is find the wrong grouping and display the error. I hope there is a better way to do this than to loop like crazy. Thank!
You should do this by traversing the elements and keeping track of the unique elements seen in HashSet<string>
and the previous value.
string previous = items.FirstOrDefault();
var seen = new HashSet<string>();
seen.Add(previous);
for (int i = 1; i < items.Count; i++)
{
if (previous != items[i])
{
if (!seen.Add(items[i]))
{
Console.WriteLine("This item is not grouped:" + items[i] + " at index " + i);
}
previous = items[i];
}
}
foreach (string item in list.Distinct())
{
int startIndex = list.IndexOf(item);
int endIndex = list.LastIndexOf(item);
bool notGrouped = Enumerable.Range(startIndex, endIndex - startIndex + 1).Select(index => list[index]).Any(i => i != item);
if (notGrouped)
{
// show message for the current item
}
}
If I understand you correctly:
List<string> orgList = .......;
bool ok = orgList.GroupBy(x => x).SelectMany(x => x).SequenceEqual(orgList);