Grouping consecutive identical items: IEnumerable to IEnumerable>

Question

I\'ve got an interresting problem: Given an IEnumerable, is it possible to yield a sequence of IEnumerable>

Answer 1

Your second bullet is the problematic one. Here's why:

var groups = CallMagicGetGroupsMethod().ToList();
foreach (string x in groups[3])
{
    ...
}
foreach (string x in groups[0])
{
    ...
}

Here, it's trying to iterate over the fourth group and then the first group... that's clearly only going to work if all the groups are buffered or it can reread the sequence, neither of which is ideal.

I suspect you want a more "reactive" approach - I don't know offhand whether Reactive Extensions does what you want (the "consecutive" requirement is unusual) but you should basically provide some sort of action to be executed on each group... that way the method won't need to worry about having to return you something which could be used later on, after it's already finished reading.

Let me know if you'd like me to try to find a solution within Rx, or whether you would be happy with something like:

void GroupConsecutive(IEnumerable items,
                      Action> action)