Ruby to C# conversion, assigning to an array indexed by range

Question

I have trouble understanding this since I'm not very familiar with Ruby and I need to convert this code to C#:

gifts[(position + 1)..-1] = []

gifts is an array, but what does this line do? Does it remove elements from (position + 1) to -1, or marks them as an empty element?

What I'm using is:

gifts.RemoveRange(0, position + 1);

If there is something particularly unclear about the documentation of Array#[]=, I'm sure the Ruby team would be happy to know about it! — Jörg W Mittag
– Jörg W Mittag, Commented Mar 25, 2015 at 9:09
@JörgWMittag: I think here it is the odd special-casing of parsing a Range end point . . . because e.g. 5..-1 will do different things inside and outside of [ ] — Neil Slater
– Neil Slater, Commented Mar 25, 2015 at 9:11
Yeah, array slicing doesn't care about the contents of the range (which in this particular case is just empty), only the start and endpoint. Makes sense, but is non-obvious. — Jörg W Mittag
– Jörg W Mittag, Commented Mar 25, 2015 at 9:25

Andrey Korneyev · Accepted Answer · 2015-03-25 09:05:46Z

3

This Ruby code gifts[(position + 1)..-1] = [] removes entries from position + 1 to -1 which is "last element of array" in Ruby.

So equivalent code in C# will be

gifts.RemoveRange(position + 1, gifts.Count- position - 1);

answered Mar 25, 2015 at 9:05

Andrey Korneyev

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Comments

knittl · Accepted Answer · 2015-03-25 09:04:10Z

3

The ruby snippet will remove everything after position:

gifts = [1,2,3,4,5];
gifts[2..-1] = [];
gifts; // [1, 2]

An equivalent C# snippet (using LINQ) would be:

gifts = gifts.Take(position+1).ToList();

Or, if you want to modify the list in-place (no LINQ required):

gifts.RemoveRange(position + 1, list.Count - position - 1);

answered Mar 25, 2015 at 9:04

knittl

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