Number Formating using regular expression and format method of String class

14 / Dec / 2010 by Salil 0 comments

Hey guys, I found something very useful, so sharing it here.
In one of my project there was a requirement to create a fixed length user-id. Let’s say it was 5 characters ID.

So in other words we required to convert
‘123’ to ‘00123’ and ‘1000’ to ‘01000’ and ‘12345’ will remain ‘12345’.
It appears very simple, but the thing is how quick we do this.

Earlier I thought to do this by calculating the length of id and prefixing required number of zeros.

Alternate single-line and faster solution is –
// following will return a String with size of 5 characters and prefixes zeros (if id has digits lesser than 5).
String.format(‘%05d’, id)
// Note down, id is a digit here.

That’s all. . isn’t it nice?. We can utilize it at many places like – converting date from ‘1-1-2010′ to ’01-01-2010’.
Idea is to introduce such kind of utility. If you already knew this, please ignore 🙂
please open the ideas – if you know something better than this.

salil at IntelliGrape dot com


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