split string using regex

Question

I am trying to use split() to get this output:

Colour = "Red/White/Blue/Green/Yellow/"
Colour = "Orange"

...but could not succeed. What am I doing wrong?

Basically I am matching the last / and splitting the string there.

String pattern = "[\\/]$";
String colours = "Red/White/Blue/Green/Yellow/Orange";

Pattern splitter = Pattern.compile(pattern);
String[] result = splitter.split(colours);

for (String colour : result) {
    System.out.println("Colour = \"" + colour + "\"");
}

Are you trying to get individual colors or just the last color? — Chandu
– Chandu, Commented Mar 4, 2011 at 4:56

codaddict · Accepted Answer · 2011-03-04 04:59:39Z

3

You need to split the string on the last /. The regex to match the last / is:

/(?!.*/)

See it on IdeOne

Explanation:

/       : A literal /
(?!.*/) : Negative lookahead assertion. So the literal / above is matched only 
          if it is not followed by any other /. So it matches only the last /

answered Mar 4, 2011 at 4:59

codaddict

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2 Comments

Alan Moore Over a year ago

+1. Or, if you really have to retain the slash at the end of the first token, you can use (?<=/(?=[^/]*$)) instead. :D

codaddict Over a year ago

@Alan: You are right..looks like OP wants to have the / at the end.

Mohamed Mansour · Accepted Answer · 2011-03-04 04:58:12Z

1

Your pattern is incorrect, you placed the $ that says it must end with a /, remove $ and it should work fine.

While we are at it, you could just use the String.split

String colours = "Red/White/Blue/Green/Yellow/Orange";
String[] result = colours.split("\\/");

for (String colour : result) {
    System.out.println("Colour = \"" + colour + "\"");
}

answered Mar 4, 2011 at 4:58

Mohamed Mansour

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1 Comment

Ted Hopp Over a year ago

I think OP wanted the string split into exactly two parts, with the split at the last /. You'd have to join all but the last part back together with / to get what was required.

Ted Hopp · Accepted Answer · 2011-03-04 17:03:15Z

1

How about:

int ix = colours.lastIndexOf('/') + 1;
String[] result = { colours.substring(0, ix), colours.substring(ix) };

(EDIT: corrected to include trailing / at end of first string.)

edited Mar 4, 2011 at 17:03

answered Mar 4, 2011 at 4:57

Ted Hopp

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