Find and extract all numbers from the String

Question

I have a string like: "Hello I'm 43 years old, I need 2 burgers each for 1.99$". I need to parse it and get all the numbers in it as double. So the function should return an array of values like: 43, 2, 1.99. In C++ I should've write all by myself, but C# has Regex and I think it may be helpful here:

String subjectString = "Hello I'm 43 years old, I need 2 burgers each for 1.99$";
resultString = Regex.Match(subjectString, @"\d+").Value;
double result = double.Parse(resultString);

After this, the resultString is "43" and result is 43.0. How to parse the string to get more numbers?

As for me, this question has more complete answer, so make a decision. — Netherwire, Dec 06 '13 at 12:33

CodingIntrigue · Accepted Answer · 2013-12-06T11:54:25.467

5

Your regex needs to be a little more complex to include decimals:

\d+(\.\d+)?

Then you need to get multiple matches:

MatchCollection mc = Regex.Matches(subjectString, "\\d+(\\.\\d+)?");
foreach (Match m in mc)
{
    double d = double.Parse(m.Groups[0].Value);
}

Here is an example.

edited Dec 06 '13 at 11:54

answered Dec 06 '13 at 11:48

CodingIntrigue

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Be sure to check for locale issues if needed. Not everyone uses the same decimal separator. – GaussZ Dec 06 '13 at 11:52
@GaussZ you mean dot or comma? – Netherwire Dec 06 '13 at 11:52
@GaussZ Good point. Yes, could be dot or comma. Also perhaps you input also needs to take care of thousands separators? – CodingIntrigue Dec 06 '13 at 11:53
@RomanChehowsky Yes. Also usually the 10^3 separator is the opposite (comma for dot-decimal-separators and vice versa). – GaussZ Dec 06 '13 at 11:54

score 2 · Answer 2 · answered Dec 06 '13 at 11:49

2

Try to use the following regular expression:

-?[0-9]+(\.[0-9]+)?

and then use Regex.Matches and iterate over the matches returned.

answered Dec 06 '13 at 11:49

Tobias Ramforth

161
3

score 1 · Answer 3 · answered Dec 06 '13 at 11:51

You should use Matches method to get a collection of matches. Also, you need to add dot to your regex

String subjectString = "Hello I'm 43 years old, I need 2 burgers each for 1.99$";
var matches = Regex.Matches(subjectString, @"\d+(\.\d+)?");

for (int i = 0; i < matches.Count; i++ )
{
    double d = double.Parse(matches[i].Value);
}

Find and extract all numbers from the String

3 Answers3