C# string search

Question

I have string which contain white space like

string str="Option (A) and option (   B   ) and (c     )"

If and i want to search (A) (B) (C) position and length I know I can use string.replace(" ","") and search.

Here I know (B) is there but due to white space I am not able to get correct Index and Length .

For example in this case I want str.IndexOf("(B)",0) should return 22(I calculated manually). and also get length I mean my program should know here (B) start index=22 and length=9 (here length of (B) is not 3 because in string due to white space its increase to 9.

Thanks

i have to use that index for further in non edited string .. If i will use str.replace it will not give correct index — Ajeet
– Ajeet, Commented Mar 20, 2017 at 14:52
You might want to try regular expressions that allow you to search for optional whitespace something like \(\w*B\w*\). — juharr
– juharr, Commented Mar 20, 2017 at 14:52
@Nino no it may be one or more than one character and any number of white space may come — Ajeet
– Ajeet, Commented Mar 20, 2017 at 14:54

Wiktor Stribiżew · Accepted Answer · 2017-03-20 15:00:24Z

3

Use a regex for this:

var str = "Option (A) and option (   B   ) and (c     )";
var matches = Regex.Matches(str, @"\([^()]*\)");
foreach (Match match in matches) {
    Console.WriteLine("Value: {0}", match.Value);
    Console.WriteLine("Position: {0}",match.Index);
    Console.WriteLine("Length: {0}",match.Length);
}

See the C# demo

A Match object has the necessary Index and Length properties you may access after getting all the matches.

The pattern here matches:

\( - a literal (
[^()]* - zero or more chars other than ( and )
\) - a literal ).

You may adjust it say, to match (, 0+ whitespaces, a letter, zero or more whitespaces and a ) by using @"\(\s*\p{L}\s*\)".

edited Mar 20, 2017 at 15:00

answered Mar 20, 2017 at 14:56

Wiktor Stribiżew

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3 Comments

Ajeet Over a year ago

Everything is fine but what if we want to search some string(it may be (A) or any other string foo) in other string str ?

Wiktor Stribiżew Over a year ago

@Ajeet: The current question does not really contain the requirements for what there must appear inside parentheses, that is why I suggested a rather generic pattern. The pattern can be adjusted more or less easily, but the requirements should be provided first.

Wiktor Stribiżew Over a year ago

So, you just need @"\([\sa-zA-Z]*\)", right? Whitespace or letter symbols only inside parentheses?

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