CODEWITHSUNDEEP
javaregexsplit
user793491
user793491

Reputation: 193

Having trouble using regular expressions with the split method in java

I have a list of strings that I need to parse for the name and version, for example some strings look like this:

App Name 1.2.5
AppName 7.8.b
The App Name 7.0

I want to have two list of Strings one with the app name and one with the version number so one list is:

App Name
AppName
The App Name

Then the other list will be

1.2.5
7.8.b
3.0

I have tried just using a space to split the strings, but it would be easiest if the name was always in index 0 and the version is always in index 1. So I tried "\\d" (split by digits), however that didn't work like I thought it was. Any help would be appreciated, and thanks in advance

Upvotes: 2

Views: 317

Answers (2)

user85421
user85421

Reputation: 29680

Try with " (?=\\d)"

that is a space followed by an digit which is not consumed (via zero-width positive lookahead)

Upvotes: 0

Mike Samuel
Mike Samuel

Reputation: 120516

Split isn't really appropriate here. Try using a matcher instead and use the group method to get the app name and version.

Pattern p = Pattern.compile("^(\\D*[^\\d\\s])\\s*(\\d.*)", Pattern.DOT_ALL);
Matcher m = p.matcher(myString);
if (m.find()) {
  String appName = m.group(1);
  String versionNumber = m.group(2);
  ...
}

To understand how the regular expression works, take a look at the below:

^

means start matching at the start

(

starts group 1 which will hold the version name

\\D*

which starts with any number of non-digits

[^\\d\\s]

and ends with something that is neither a digit nor a space.

)

end of group 1

\\s*

which might be separated from the version number by zero or more spaces.

(

Group 2 contains the version number.

\\d

It starts with a digit

.*

and continues the rest of the input.

)

The end.

Upvotes: 5

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