Regex to extract numeric string

Question

Hi I don't feel very well with regular expressions. What I would like to achieve is to extract a numeric substring (only 0-9 digits) from the input string.

The numeric string that is searched should be preceded only by a semicolon (;), space ( ) or should be placed exactly at the begining of the input (not line).
The numeric string that is searched should be followed only by a semicolon (;), the end of line or the end of the input string.

Exemplary input:

;x; ;SrvId=3993;ad257c823; 435223;

Output:

435223

I tried: [ \A|;|[ ]]\d*[\r|;|\Z] but it did not worked, it did not even compiled.

FailedDev · Accepted Answer · 2011-10-12 08:55:35Z

2

Try this one:

string resultString = null;
try {
    resultString = Regex.Match(subjectString, @"(?<=\A|\s+|;)(\d+)(?=$|;|\Z)").Groups[1].Value;
} catch (ArgumentException ex) {
    // Syntax error in the regular expression
}

Break down :

(?<=\A|\s+|;)

Posiive lookbehind : start of input or at least one whitespace character or a semicolon.

(\d+) at least one digit

(?=$|;|\Z)

Positive lookahead either end of line, or semicolon or and of input.

Input : ;x; ;SrvId=3993;ad257c823; 435223;

Output of group 1 : 435223

edited Oct 12, 2011 at 8:55

answered Oct 12, 2011 at 8:49

FailedDev

26.9k9 gold badges54 silver badges73 bronze badges

@HasanKhan Can you provide an input which makes it to match where it shouldn't match?
– FailedDev
Commented Oct 12, 2011 at 11:41
@FailedDev it doesn't match the number at the end of line when there is more text in new line
– Muhammad Hasan Khan
Commented Oct 13, 2011 at 4:31
@HasanKhan I don't see any new line in OP examples. Do you?
– FailedDev
Commented Oct 13, 2011 at 6:44
@FailedDev "The numeric string that is searched should be followed only by a semicolon (;), the end of line or the end of the input string."
– Muhammad Hasan Khan
Commented Oct 13, 2011 at 6:47
@HasanKhan You can write whatever bold letters you want, however this still doesn't change the fact that there is no new line in the OPs post :) Also if my english don't deceive me the end of line should be the last part of the string. OP doesn't mention possibility of multiple new lines. So you are wrong - again :D
– FailedDev
Commented Oct 13, 2011 at 6:59

Add a comment |

Aziz Shaikh · Accepted Answer · 2011-10-12 08:55:00Z

1

Try this regex:

^(?:[; ]?)(?:.*?)([0-9]+);$

answered Oct 12, 2011 at 8:55

Aziz Shaikh

16.6k11 gold badges65 silver badges81 bronze badges

Add a comment |

user489998 · Accepted Answer · 2011-10-12 08:55:35Z

1

Using ^.*[ ;](\d+)[;\n]?$ will capture the numbers you're interested in although you may have to change the \n to \r\n depending on the line endings of your input file.

answered Oct 12, 2011 at 8:55

user489998

4,5312 gold badges31 silver badges36 bronze badges

Add a comment |

Fischermaen · Accepted Answer · 2011-10-12 08:45:55Z

0

The regular expression should be this:

"[; ]{1}[0-9]+($|[^0-9]+)"

answered Oct 12, 2011 at 8:45

Fischermaen

12.5k2 gold badges42 silver badges56 bronze badges

This returns 435223; which includes the semi-colon
– Simon Hughes
Commented Oct 12, 2011 at 9:05

Add a comment |

Chief · Accepted Answer · 2011-10-12 09:03:18Z

0

Try using this expression

(\d+\.?\d*|\.\d+)

answered Oct 12, 2011 at 9:03

Chief

9141 gold badge9 silver badges26 bronze badges

Add a comment |

Collectives™ on Stack Overflow

Regex to extract numeric string

5 Answers 5

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

Related