正则表达式匹配字符串

Question

I have array of strings with following data:

'STSO/82465'
'CPB'
550
'B'
'IEC2'
'IEC2'
50
525
680
1550,1175
'500000/V3'
'23585/V3'
''
etc...

Positions marked with '' are strings rest is double, I need help with regex to get only strings.

Answer 1

Why do you need regex for this?

double d;
string[] noDoubles = Array.FindAll(arr, s => !double.TryParse(s, out d));

this accepts the decimal separator of the current culture. You can change it if you use the overload of double.TryParse . It seems to be , for you as your sample data suggests.

If you want to allow point as decimal separator:

Array.FindAll(arr, s => !double.TryParse(s, NumberStyles.Any, NumberFormatInfo.InvariantInfo, out d));

If the non-doubles really start all with ' you could also make it simpler:

string[] noDoubles = Array.FindAll(arr, s => s.StartsWith("'"));

Answer 2

the String 's StartsWith EndsWith methods should do the trick:

var tab = new[]
        {
            "'STSO/82465'",
            "'CPB'",
            "550",
            "'B'",
            "'IEC2'",
            "'IEC2'",
            "50",
            "525",
            "680",
            "1550,1175",
            "'500000/V3'",
            "'23585/V3'"
        };
        foreach (var s in tab)
        {
            if (s.StartsWith("'") && s.EndsWith("'"))
            {
                //use the s
            }
        }

Answer 3

LINQ one-liner:

var linesWithStrings = allLines.Where( l => l.StartsWith( "'" ) );

Or, if you want to strip the quotes:

var linesWithStrings = from s in allLines
                       where s.Length >= 2 && s.StartsWith( "'" ) && s.EndsWith( "'" )
                       select s.Substring( 1, s.Length - 2 );