收录日期:2020/07/05 17:09:31 时间:2010-07-01 22:40:11 标签:c#,list,arrays

.ToArray doesn't do it

One quick variation on the existing answers, which uses a method group conversion instead of a lambda expression:

string[][] array = lists.Select(Enumerable.ToArray).ToArray();

In theory it'll be every so slightly faster, as there's one less layer of abstraction in the delegate passed to Select.

Remember kids: when you see a lambda expression of this form:

foo => foo.SomeMethod()

consider using a method group conversion. Often it won't be any nicer, but sometimes it will :)

Getting back to a List<List<string>> is easy too:

List<List<string>> lists = array.Select(Enumerable.ToList).ToList();

Linq is the way to go on this one.

List<List<String>> list = ....;
string[][] array = list.Select(l => l.ToArray()).ToArray();

to break it down a little more the types work out like this:

List<List<String>> list = ....;
IEnumerable<String[]> temp = list.Select(l => l.ToArray());
String[][] array = temp.ToArray();
List<List<string>> myStrings;

myStrings.Select(l => l.ToArray()).ToArray();

(LINQ rocks)