Extract decimal Number from string in C#

Question

I am trying to extract numbers from my string using the following code:

var mat = Regex.Match(stringValue, @"\d+").Value;

But when stringValue contains a decimal like "($23.01)", It only extracts 23 instead of 23.01. How can I get the decimal value 23.01?

Solution 1

Try to approach the problem this way. A decimal number has the following features:

• start with one or more digits (\d+)
• after that, there can be one or 0 dots (\.?)
• if a dot is present, one or more digits should also follow (\d+)

Since the last two features are kind of related, we can put it in a group and add a ? quantifier: (\.\d+)?.

So now we have the whole regex: \d+(\.\d+)?

If you want to match decimal numbers like .01 (without the 0 at the front), you can just use | to mean "or" and add another case (\.\d+). Basically: (\d+(\.\d+)?)|(\.\d+)

Solution 2

Have you tried this Example:

string inputStr =  "($23.01)";      
Console.WriteLine(Regex.Match(inputStr, @"\d+.+\d").Value);

Or else you can try this LinqSolution:

Console.WriteLine(String.Concat(inputStr.Where(x=> x=='.'||Char.IsDigit(x))));

Comments

[xunatai]

10. or .01 aren't valid decimal numbers?

[Sweeper]

@xunatai No I don't consider them as decimal numbers

[Sweeper]

@xunatai 10. will just match 10 anyway. And you just need to do \d* instead of \d+ at the start to match .01

[Sweeper]

@xunatai Oops! That was my quick thinking. (\d+(\.\d+)?)|(\.\d+) should work.

[Huma Ali]

when string contains "($23)", This will fail

[sujith karivelil]

@HumaAli: Regex will fail with that input you can try the Linq solution then

[Huma Ali]

@Sweeper will it work if string contains "($23)" and no decimal value?

[Sweeper]

@HumaAli it will. Why not try it for yourself?

[Huma Ali]

@Sweeper Just did. It works :)

[Rob Sedgwick]

just add a question mark at the end: \d+.+\d?