How to remove the first element in an array?

Question

I have an array:

arr[0]="a"  
arr[1]="b"  
arr[2]="a"

I want to remove only arr[0], and keep arr[1] and arr[2].
I was using:

arr= arr.Where(w => w != arr[0]).ToArray();

Since arr[0] and arr[2] have the same value ("a"), the result I'm getting is only arr[1].

How can I return both arr[1] and arr[2], and only remove arr[0]?

this is just one of the many reasons a List would be a better choice — Ňɏssa Pøngjǣrdenlarp, Jan 15 '15 at 14:07
You could have used a different overload that supplies an index: `.Where((w, i) => i > 0)` but `.Skip(1)` would remove the need to even worry about your conditional. — spender, Jan 15 '15 at 14:12

score 233 · Accepted Answer · edited Oct 25 '17 at 13:04

233

You can easily do that using Skip:

arr = arr.Skip(1).ToArray();

This creates another array with new elements like in other answers. It's because you can't remove from or add elements to an array. Arrays have a fixed size.

edited Oct 25 '17 at 13:04

Mark Amery

143,130
81
406
459

answered Jan 15 '15 at 14:09

Selman Genç

100,147
13
119
184

Yep. Very straight forward. – spender Jan 15 '15 at 14:11
Haven't seen this before. Very nice. It's so nice to slowly get to know your tools properly and to learn what functionality they contain. Thanks. – lenny Jul 04 '19 at 07:12
8

To use this (and other answers to the question), you need the declaration `using System.Linq;` – Chris Halcrow Sep 23 '19 at 05:49
I wish there is an official extension for something like `.DropFirst()` – mr5 Mar 03 '20 at 06:41

score 23 · Answer 2 · edited Nov 16 '20 at 23:34

23

You could try this:

arr = arr.ToList().RemoveAt(0).ToArray();

We make a list based on the array we already have, we remove the element in the 0 position and cast the result to an array.

or this:

arr = arr.Where((item, index)=>index!=0).ToArray();

where we use the overloaded version of Where, which takes as an argument also the item's index. Please have a look here.

Update

Another way, that is more elegant than the above, as D Stanley pointed out, is to use the Skip method:

arr = arr.Skip(1).ToArray();

edited Nov 16 '20 at 23:34

Theodor Zoulias

34,835
7
69
104

answered Jan 15 '15 at 14:03

Christos

53,228
8
76
108

2

The first solution does't work as `RemoveAt(0)` is a procedure and it doesn't return a list so that you can call `ToArray()` on... – n1nsa1d00 May 26 '16 at 23:01
I revoked the last edit because it doesn't improve the answer IMHO. – Theodor Zoulias Nov 16 '20 at 23:36

score 2 · Answer 3 · answered Jan 15 '15 at 14:04

2

Use second overload of Enumerable.Where:-

arr = arr.Where((v,i) => i != 0).ToArray();

answered Jan 15 '15 at 14:04

Rahul Singh

21,585
6
41
56

score 2 · Answer 4 · answered Jan 15 '15 at 14:04

2

How About:

if (arr.Length > 0)
{
    arr = arr.ToList().RemoveAt(0).ToArray();
}
return arr;

answered Jan 15 '15 at 14:04

User999999

2,500
7
37
63

How to remove the first element in an array?

4 Answers4

Linked

Related