for example when I wrote:
Char[] test = new Char[3] {a,b,c};
test[2] = null;
it says Cannot convert null to 'char' because it is a non-nullable value type
if I need to empty that array of char, is there a solution?
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5see Why is there no Char.Empty like String.Empty?Michal Klouda– Michal Klouda2012-10-10 19:52:44 +00:00Commented Oct 10, 2012 at 19:52
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I have edited your title. Please see, "Should questions include “tags” in their titles?", where the consensus is "no, they should not".John Saunders– John Saunders2012-10-10 20:23:30 +00:00Commented Oct 10, 2012 at 20:23
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6 Answers
Use a nullable char:
char?[] test = new char?[3] {a,b,c};
test[2] = null;
The drawback is you have to check for a value each time you access the array:
char c = test[1]; // illegal
if(test[1].HasValue)
{
char c = test[1].Value;
}
or you could use a "magic" char value to represent null, like \0:
char[] test = new char[3] {a,b,c};
test[2] = '\0';
4 Comments
jheddings
Just a quick suggestion might be to use
default(char) for the "magic" value. IMHO, it provides a similar mental model for considering the value "uninitialized" or "unspecified."
D Stanley
Fair enough - using
\0 as null is a holdover from my C++ days :)jheddings
Nothing wrong with that... They are the same in this case, after all.
Hendra Anggrian
that '\0' works perfectly. I'm sorry I have to ignore the first 2 packs of codes above because I'm searching for the simplest one. Thanks mate!
You can't do it because, as the error says, char is a value type.
You could do this:
char?[] test = new char?[3]{a,b,c};
test[2] = null;
because you are now using the nullable char.
If you don't want to use a nullable type, you will have to decide on some value to represent an empty cell in your array.
Comments
You could do:
test[2] = Char.MinValue;
If you had tests to see if a value was "null" somewhere in your code, you'd do it like this:
if (test[someArrayIndex] == Char.MinValue)
{
// Do stuff.
}
Also, Char.MinValue == default(char)
Comments
As the error states, char is non-nullable. Try using default instead:
test[2] = default(char);
Note that this is essentially a null byte '\0'. This does not give you a null value for the index. If you truly need to consider a null scenario, the other answers here would work best (using a nullable type).
2 Comments
Jeppe Stig Nielsen
default(char) gives the null character. Why not make that explicit and say test[2] = '\0';? I would recommend that (if you want to use this character as a kind of "magic value").jheddings
Only for consistency... I use
default in many cases where the type is not know up front (i.e. generics or reflection). It helps me keep a consistent mental model that default => "unspecified" or "uninitialized."you can set test to null
test = null;
but not test[2] because it is char - hence value type
Comments
I don't know the reason for your question, but if instead you use List<>, you could say
List<char> test = new List<char> { a, b, c, };
test.RemoveAt(2);
This changes the length (Count) of the List<>.
answered Oct 10, 2012 at 20:12
Jeppe Stig Nielsen
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