extracting integer from string

Question

This might be really simple but i have a service that returns a string that has a number preceded with zeros. The count of zeros is not predictable but i need to extract the number out of the value. The length of the value is also not constant. For ex. 00001234, 002345667, 0000000, 011, 00000987 - in all these values, i need to extract the 1234, 2345667, <no value>, 11, 987. i have tried doing the below code but it returns the zeros as well:

string.Join( null,System.Text.RegularExpressions.Regex.Split( expr, "[^\\d]" ) );

Can anyone help?

Got my Answer::

I got it using stringObj.TrimStart('0'). But i agree using Int.Parse or Int.TryParse is a better way of handling. Hope this is useful to someone like me!

So how does TrimStart handle values like -000012? Or will you always have positive integers? — FrustratedWithFormsDesigner
– FrustratedWithFormsDesigner, Commented Jul 27, 2011 at 18:41
yes, it will always be positive integers but I would agree using int.Parse or Int.TryParse is a better option. — user583126
– user583126, Commented Jul 27, 2011 at 18:47

dkackman · Accepted Answer · 2011-07-27 18:36:36Z

7

int ret;

if (int.TryParse("0001234", out ret))
{
    return ret.ToString();
}

throw new Exception("eep");

answered Jul 27, 2011 at 18:36

dkackman

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2 Comments

Jake Kalstad Over a year ago

Cleanest code, TryParse is never as slick, but much higher quality than a straight parse.

JK. Over a year ago

Agree to that. But I believe that OP prefer a cast. +1

Justin Niessner · Accepted Answer · 2011-07-27 18:36:58Z

2

var numString = "00001234, 002345667, 0000000, 011, 00000987";

// result will contain "1234, 2345667, <no value>, 11, 987"
var result = string.Join(", ", numString.Split().Select(s => 
    {
        var intVal = int.Parse(s);
        return intVal == 0 ? "<no value>" : intVal.ToString();
    }));

answered Jul 27, 2011 at 18:36

Justin Niessner

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Comments

JK. · Accepted Answer · 2011-07-27 18:36:15Z

1

Cast to integer and back to string?

int num    = Convert.ToInt32(val);
string val = Convert.ToString(num);

answered Jul 27, 2011 at 18:36

JK.

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Comments

abney317 · Accepted Answer · 2011-07-27 18:42:01Z

1

This should do the trick

string s = "0005";
string output = Convert.ToInt32(s.TrimStart(Convert.ToChar("0")));

answered Jul 27, 2011 at 18:42

abney317

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Comments

Nicholas Carey · Accepted Answer · 2011-07-27 20:31:31Z

1

The power of regular expressions to the rescue!

static readonly Regex rx = new Regex( @"[^\d]*((0*)([1-9][0-9]*)?)" ) ;
public static IEnumerable<string> ParseNumbers( string s )
{
  for ( Match matched = rx.Match(s) ; matched.Success ; matched = matched.NextMatch() )
  {
    if ( matched.Groups[1].Length > 0 )
    {
      yield return matched.Groups[3].Value ;
    }
  }
}

Passing the string "00001234, 002345667, 0000000, 011, 00000987" to ParseNumbers() yields the enumeration

"1234"
"2345667"
""
"11"
"987"

Cheers!

answered Jul 27, 2011 at 20:31

Nicholas Carey

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Comments

FiveTools · Accepted Answer · 2011-07-27 18:35:38Z

0

000000 is 0 not null....

int intInteger = -1;
int.tryparse(stringNumber,out intInteger);

should give you a clean integer.

answered Jul 27, 2011 at 18:35

FiveTools

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Comments

FrustratedWithFormsDesigner · Accepted Answer · 2011-07-27 18:37:20Z

0

you can use Int.Parse to parse the string into an integer.

    String s = "00001234, 002345667, 0000000, 011, 00000987";
    string[] nums= s.Split(',');
foreach (string num in nums
{
    Console.WriteLine(Int.Parse(num)); //you'll need special handling to print "<no value>" when the string is 0000000
}

(haven't actually compiled this)

answered Jul 27, 2011 at 18:37

FrustratedWithFormsDesigner

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