String how to partially replace special char/string

Thread view:

John_Woo - 06 Jul 2006 16:48 GMT

Hi,

I'm trying to partially replace a string with a substring, like

old = "1..2..3..4"
new="1*2*3..4"

two ways to implement:

1. old.replaceAll ("\\..","*");

2. Pattern pattern = Pattern.compile("[..]{2}");
Matcher matcher = pattern.matcher(old);

matcher.replaceAll("*");

but these two result in

1*2*3*4

Can any one tell how to force to only replacing the first #1,2,
occurrances?

--
Thanks
John
Toronto

Reply to this Message

Alex Whitney - 06 Jul 2006 17:40 GMT

Split the string up using ".." as the delimeter. Insert a * between
each element. Between the nth element and n-1, insert ".." instead.

Scanner scan = new Scanner (old);
scan.useDelimiter (Pattern.compile("[..]{2}");

String newStr = "";
newStr = scan.next(); // Run time error if old is empty.
while (scan.hasNext())
{
String next = scan.next();

if (scan.hasNext())
newStr = newStr + "*" + next;
else
newStr = newStr + ".." + next;
}

> Hi,
>
[quoted text clipped - 23 lines]
> John
> Toronto

Reply to this Message

Alex Whitney - 06 Jul 2006 17:44 GMT

Oops.

Scanner scan = new Scanner (old);
scan.useDelimiter (Pattern.compile("[..]{2}");

String newStr = "";
newStr = scan.next(); // Run time error if old doesn't have enough
data...
newStr = newStr + "*" + scan.next();
newStr = newStr + "*" + scan.next();
while (scan.hasNext())
{
String next = scan.next();

if (!scan.hasNext())
newStr = newStr + ".." + next;
}

> Split the string up using ".." as the delimeter. Insert a * between
> each element. Between the nth element and n-1, insert ".." instead.
[quoted text clipped - 41 lines]
> > John
> > Toronto

Reply to this Message

Lasse Reichstein Nielsen - 06 Jul 2006 17:55 GMT

> I'm trying to partially replace a string with a substring, like
>
[quoted text clipped - 4 lines]
>
> 1. old.replaceAll ("\\..","*");

You probably also want to escape the second ".".

> 2. Pattern pattern = Pattern.compile("[..]{2}");

What are you expecting this pattern to match? It matches
exactly the same as "\\.\\." or "[.][.]".

> Can any one tell how to force to only replacing the first #1,2,
> occurrances?

1) Use String.replaceFirst twice.
2) Use split+join:
String[] parts = old.split("\\.\\.",3);
newString = parts[0] + "*" + parts[1] + "*" + parts[2];

/L

Signature

Lasse Reichstein Nielsen - lrn@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleDOM.html>
'Faith without judgement merely degrades the spirit divine.'

Reply to this Message

shakah - 06 Jul 2006 21:34 GMT

> Hi,
>
[quoted text clipped - 23 lines]
> John
> Toronto

What about a simple:

old.replaceFirst("\\.\\.", "*").replaceFirst("\\.\\.", "*") ;

?

Reply to this Message

String how to partially replace special char/string

Free Magazines