Select parsed int, if string was parseable to int

by

It’s hard to do that in query syntax, but it’s not too bad in lambda syntax:

var ints = strings.Select(str => {
                             int value;
                             bool success = int.TryParse(str, out value);
                             return new { value, success };
                         })
                  .Where(pair => pair.success)
                  .Select(pair => pair.value);

Alternatively, you may find it worth writing a method which returns an int?:

public static int? NullableTryParseInt32(string text)
{
    int value;
    return int.TryParse(text, out value) ? (int?) value : null;
}

Then you can just use:

var ints = from str in strings
           let nullable = NullableTryParseInt32(str)
           where nullable != null
           select nullable.Value;

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