C# string comparision error

Question

I am trying to check if value exists in a string array. The below one works but when I tried the next code block, it failed.

bool exixts;
string toCheck= "jupiter";

string[] printer = {"jupiter", "neptune", "pangea", "mercury", "sonic"};

if(printer.Contains(toCheck))
{
    exists = true;
}

How can I check for trim and case sensitivity?

I tried this

bool exixts;
string toCheck= "jupiter   ";

string[] printer = {"jupiter", "neptune", "pangea", "mercury", "sonic"};
 if(printer.Contains(toCheck.Trim(),StringComparison.InvariantCultureIgnoreCase)))
{
    exists = true;
}

score 2 · Answer 1 · answered Oct 16 '16 at 22:42

The IEnumerable<string>.Contains(value, comparer) expects a compare class instance, not an enum value.

The library does have some ready made comparers available though:

//if(printer.Contains(toCheck.Trim(),StringComparison.InvariantCultureIgnoreCase)))
if (printer.Contains(toCheck.Trim(), StringComparer.OrdinalIgnoreCase))

score 1 · Accepted Answer · answered Oct 16 '16 at 22:51

1

Or you can do like this,

bool exists = printer.Any(x=> x == toCheck.Trim());

Hope helps,

answered Oct 16 '16 at 22:51

Berkay Yaylacı

4,293
2
18
34

.Any is better or .contains is better which one is preferable? – Kurkula Oct 16 '16 at 22:57
1

@Kurkula Check [this](http://stackoverflow.com/questions/23526773/what-is-the-difference-between-contains-and-any-in-linq). In my opinion, Any is better bacause of the comparision. – Berkay Yaylacı Oct 16 '16 at 23:03
will Any do StringComparer.OrdinalIgnoreCase also? – Kurkula Oct 16 '16 at 23:18
1

@Kurkula No, but at comparision you can use ToLower(). Which will convert string's all letters to lower case. – Berkay Yaylacı Oct 16 '16 at 23:22
in this case .toLower() should be used on source and destination value? – Kurkula Oct 16 '16 at 23:55
1

@Kurkula Only `toCheck.Trim().ToLower()` will be enough. – Berkay Yaylacı Oct 16 '16 at 23:57
`Any()` is better and you can replace the `==` with `String.Equals()` to use InvariantCultureIgnoreCase. Using `ToLower()` is an awful idea. – Henk Holterman Oct 17 '16 at 06:29

C# string comparision error

2 Answers2