CODEWITHSUNDEEP
javaregextokenizesplit
assassin
assassin

Reputation: 21179

regular expressions in java

I have a problem where I need to tokenize my string (using java code) so that it is split into a String array. Each token in this array should be either a word, number or dimensions of the form (23 x 34 x 56, etc.) I tried to code this as:

String[] split_text = text.split("\\s | (\\d{3},)*\\d{3}([.]\\d)* x (\\d{3},)*\\d{3}([.]\\d)* | \\d*([.]\\d)* x \\d*([.]\\d)*");

But, this is giving a syntax error. Can anyone please tell me how I can do this using regular expressions, and whether there is a problem in the way I have expressed the regular expression in java?

Upvotes: 0

Views: 234

Answers (3)

morja
morja

Reputation: 8560

To match any pair of numbers with dots or commas and an x in the middle you could do something like this:

(\d*(?:[.,]\d+)* x \d*(?:[.,]\d+)*)

or for pairs and triples:

(\d*(?:[.,]\d+)*(?: x \d*(?:[.,]\d+)*){1,2})

so maybe thats your expression:

((?:\d*(?:[.,]\d+)*(?: x \d*(?:[.,]\d+)*){1,2})|\s|\w+)

See here: http://rubular.com/r/snAiI7GMT7 - a great site for testing.

You might want to replace the \w with \p{L} to cover all unicode words in java.

Upvotes: 1

Tim Pietzcker
Tim Pietzcker

Reputation: 336378

I don't see a syntax error in your regex, but there are a few problems:

  • Whitespace is significant in a regex, so don't put spaces in the regex where you're not expecting them in the string.
  • Use \. to match a literal dot.
  • (\d{3},)*\d{3}([.]\\d)* will match 123,456,789.1.1.1.1 but not 1,234.67. Is that really what you intended?
  • <number> x <number> will only match pairs of numbers, not triplets as in your example.

I think it's best if you update your specifications a little. What exactly do you/don't you want to match. Give a few examples. Think of corner cases (is a leading zero allowed? can it be dropped as in .12? How about 1.4E-45 and so on)...

Upvotes: 0

codaddict
codaddict

Reputation: 455272

The String.split returns an array of Strings.

Make split_text an array:

String[] split_text = ...
      ^^

Upvotes: 0

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