Initialize an integer array with a single value in C# .NET [duplicate]

Question

Possible Duplicate:
How do I quicky fill an array with a specific value?

Is there a way to initialize an integer array with a single value like -1 without having to explicitly assign each item?

Basically, if I have

int[] MyIntArray = new int[SomeCount];

All items are assigned 0 by default. Is there a way to change that value to -1 without using a loop? or assigning explicitly each item using {}?

Also check out this stackoverflow.com/questions/13980570/… which discusses how to do it efficiently and stackoverflow.com/questions/10519275/… how not to use ToArray for large arrays. — Alexei Levenkov
– Alexei Levenkov, Commented Jan 8, 2013 at 7:55

Eren Ersönmez · Accepted Answer · 2013-01-08 07:54:19Z

45

int[] myIntArray = Enumerable.Repeat(-1, 20).ToArray();

edited Jan 8, 2013 at 7:54

Eren Ersönmez

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answered Jan 8, 2013 at 7:48

scartag

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4 Comments

mlorbetske Over a year ago

Don't forget the .ToArray()

Alexei Levenkov Over a year ago

+1 for all ToArray once. Before using please read High memory consumption with Enumerable.Range if your array is large.

dlchambers Over a year ago

And for types other than int, use the template form, eg. Enumerable.Repeat<UInt32>(1,20).ToArray();

tuespetre Over a year ago

@dlchambers or Enumerable.Repeat(1U, 20).ToArray();

SWeko · Accepted Answer · 2013-01-08 07:48:45Z

18

You could use the Enumerable.Repeat method

int[] myIntArray = Enumerable.Repeat(1234, 1000).ToArray()

will create an array of 1000 elements, that all have the value of 1234.

answered Jan 8, 2013 at 7:48

SWeko

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1 Comment

ozgur Over a year ago

Only answer that is clear.

Habib · Accepted Answer · 2013-01-08 07:55:36Z

15

If you've got a single value (or just a few) you can set them explicitly using a collection initializer

int[] MyIntArray = new int[] { -1 };

If you've got lots, you can use Enumerable.Repeat like this

int[] MyIntArray = Enumerable.Repeat(-1, YourArraySize).ToArray();

edited Jan 8, 2013 at 7:55

Habib

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answered Jan 8, 2013 at 7:45

mlorbetske

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3 Comments

Farhan Hafeez Over a year ago

put some size in new int[Size] and this statement will not work. Even if you put a static size like 50. So, I don't think that this is right answer.

mlorbetske Over a year ago

@FarhanHafeez You're absolutely correct, I originally misread the question and immediately went to edit my answer, my apologies

Paul Childs Over a year ago

Only answer to address the "without using a loop"

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