Java regex - Extract all float numbers before specific unit in String

Question

I am a newbie in java regex. I would like to know how to extract numbers or float numbers before %. For example:

"Titi 10% Toto and tutu equals 20X"
"Titi 10.50% Toto and tutu equals 20X"
"Titi 10-10.50% Toto and tutu equals 20X
"Titi 10sd50 % Toto and tutu equals 20X
"Titi 10-10.50% or 10sd50 % Toto and tutu equals 20X

Output :

10
10.50
10-10.50
10sd50
10-10.50;10sd50

My idea is to replace all before and after "space + number(% or space%)" by ; in order to extract all values or group values before %. I tried to use that: replaceAll("[^0-9.]+|\\.(?!\\d)(?!\\b)\\%",";"); = NO SUCCESS

How can I do it?

Not my downvote, but might be better suited by a parser. You can start by splitting the string on space, and then examining each word (possibly using a regex) to see it be a) a candidate for retention, and if so, then b) strip off the stuff you don't want. — Tim Biegeleisen
– Tim Biegeleisen, Commented Jan 16, 2017 at 10:00
Thank you. I know this is a trivial task for Java users but I am not an expert !!! I would like to learn more about that. I try your solution. Thanks a lot Tim — B.Gees
– B.Gees, Commented Jan 16, 2017 at 10:07
Next time you post please include the code you have tried. SO is not a free code writing service and most folks resent questions which show little/no effort but ask for a complex answer. — Tim Biegeleisen
– Tim Biegeleisen, Commented Jan 16, 2017 at 10:12
Why did you replace +/- with sd? Was this done by your program, intentionally or unintentionally? — merlin2011
– merlin2011, Commented Jan 16, 2017 at 10:35

Toto · Accepted Answer · 2017-01-16 10:54:13Z

2

This one should do the job:

((?:\d+(?:+|-|sd))?\d+(?:\.\d+)\h*%)

Explanation:

(               : start group 1
  (?:           : start non capture group
    \d+         : 1 or more digits
    (?:+|-|sd)  : non capture group that contains + or - or sd
  )?            : end group
  \d+           : 1 or more digits
  (?:           : start non capture group
    \.          : a dot
    \d+         : 1 or more digits
  )             : end group
  \h*           : 0 or more horizontal spaces
  %             : character %
)               : end of group 1

The result will be in group 1.

In java you have to double escape, I've not done it here for readability.

answered Jan 16, 2017 at 10:54

Toto

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Comments

sunkuet02 · Accepted Answer · 2017-01-16 11:37:48Z

1

You can do as follows:

First find all the matches in each string
Replace the last character(%) of each match elements with Blank
Do as your own formatting.

A java samples is given :

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {

    public static void main(String[] args) {
        final String regex = "\\d+(\\.?\\d+)?(\\+|\\-|sd)?(\\d+(\\.?\\d+)?)?[ ]*%";
        final String test_str = "\"Titi 10% Toto and tutu equals 20X\"\n"
                + "\"Titi 10.50% Toto and tutu equals 20X\"\n"
                + "\"Titi 10-10.50% Toto and tutu equals 20X\n"
                + "\"Titi 10sd50 % Toto and tutu equals 20X\n"
                + "\"Titi 10-10.50% or 10sd50 % Toto and tutu equals 20X";

        final Pattern pattern = Pattern.compile(regex);
        for(String data : test_str.split("\\r?\\n")) {
            Matcher matcher = pattern.matcher(data);
            while (matcher.find()) {
                System.out.print(data.substring(matcher.start(), matcher.end()-1) + " ") ;
            }
            System.out.println();
        }
    }
}

The above code gives :

10 
10.50 
10-10.50 
10sd50  
10-10.50 10sd50

You can do anything with these data. You can see the Explanations : Regex101

edited Jan 16, 2017 at 11:37

answered Jan 16, 2017 at 10:54

sunkuet02

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2 Comments

B.Gees Over a year ago

Thank you very much Sunkuet. And your external link is very nice :)

sunkuet02 Over a year ago

@B.Gees , If the answer helps you, then you can upvote my answer.

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