CODEWITHSUNDEEP
c#string
Loïc Lopes
Loïc Lopes

Reputation: 564

Use substring function or a regular expression

I want to extract an ID from a string which has the form "somethinguseless_XXXXX ". XXXXX is the ID I need. The string always has the same length and the format won't change over time.

I found 2 solutions to extract the ID => oldAttribute.substring(17,22) or Regex.Match(oldAttribute,@"_([0-9]{5})").Groups[1].value.

Which one do you think is better than the other?

Upvotes: 0

Views: 635

Answers (7)

Andy
Andy

Reputation: 3743

int p=5; //length of the substring    
string id = oldAttribute.substring(oldAttribute.Length-p, p)

Upvotes: 0

Mahesh KP
Mahesh KP

Reputation: 6446

its my suggestion , if the format is same and if "somethinguseless" doesn't contain _ you can use string.split();

Upvotes: 0

AbhiRoczz...
AbhiRoczz...

Reputation: 252

Go for the second one.

Regex.Match(oldAttribute,@"_([0-9]{5})").Groups[1].value

This will even work in case ur string length before underscore gets changed anyhow.

Upvotes: -1

Jamie Dixon
Jamie Dixon

Reputation: 53989

Personally I'd got for the option 3, split the string based on the underscore.

var id = "somethinguseless_XXXXXX".Split('_')[1];

You'll want to do some better testing to make sure the array is the length you want but this is the approach I'd likely take.

I know you've said that the string will always be the same length and won't change over time, but my experience tells me that things can always change and often aren't always the same.

Upvotes: 1

Mani
Mani

Reputation: 51

substring is the better option - when you know the location of the ID with in the string.

Upvotes: 0

Amir Ismail
Amir Ismail

Reputation: 3883

using Regex is more flixable than SubString but I think the performance of SubString is greater.

Upvotes: 0

dahlbyk
dahlbyk

Reputation: 77540

If the length is consistent, Substring() will work just as well and likely perform better. A quick test over a few million iterations would probably verify that assumption.

Upvotes: 2

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