C#. How to eliminate the error in this case?

Question

C++ / C#

Good afternoon.
When searching for a string in a file using a regular expression, if it does not find a result, it throws an error.
How can you eliminate the error? To continue silently if not found

output = File.ReadLines(tempOutputFile + ".txt").Single(l => Regex.IsMatch(l, "^.*[0-9][А-я].*$"));

Answer 1

try 
{
    output = File.ReadLines(tempOutputFile + ".txt").Single(l => Regex.IsMatch(l, "^.*[0-9][А-я].*$"));
} 
catch(Exception e)
{

}

Answer 2

Use SingleOrDefault instead of Single. Then output will be null if nothing is found.
If there can be more than one match then replace with FirstOrDefault, LastOrDefault