Extract Particular String from string in java

Question

I have a string like : String test = "A1=CA2=BOA2=RA4=OA11=O";
Now I want output like that : A1,A2,A2,A4,A11

If my string like :

String test = "[HEADER_1] [DATA] \n A10=T,(\"Re-N RO-25 M-N P-N (B)\"),1.0:0.8,R=25.0 F-7.829215,-4.032765 A20=B,R2,M=XY,R=29.999999999999996 F564.997550,669.454680";


public static void main(String[] args) {
    String test = "A1=CA2=BOA2=RA4=O";
    String data[] = test.split("[A-a]\\d{1,100}=");

    for (String str : data) {
      System.out.println("Split data:"+str);
    }      
}

What would be the regex for that?

What's the problem with the code that you have already written? — Erwin Bolwidt, Feb 05 '16 at 05:54
your output should contain only start from A or other letters will be there lik B1,b2, BB1,AA1 — Rahul Bhawar, Feb 05 '16 at 06:24

score 2 · Accepted Answer · edited May 23 '17 at 12:16

2

I would not use split for that. The regex for the parts that you want is /a\d+/i. If you use this and the Solution from Create array of regex matches to collect all matches in a list, you can easily create the desired output.

Converted the Regex in Java-Parlor:

public static void main(String[] args) {
    String test = "A1=CA2=BOA2=RA4=OA11=O";
    List<String> allMatches = new ArrayList<String>();
    Matcher m = Pattern.compile("(a\\d+)", Pattern.CASE_INSENSITIVE).matcher(test);

    while (m.find()) {
       allMatches.add(m.group());
    }
}

allMatches now contains A1 A2 A2 A4 A11

edited May 23 '17 at 12:16

Community

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answered Feb 05 '16 at 05:56

Martin Schneider

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I didn't vote you down, but I would not attempt to use a single regex here. The reason is that regex does not work so well in the case of an unbounded number of matches, which is precisely what the OP has. – Tim Biegeleisen Feb 05 '16 at 05:58
Could you explain which cases you mean? – Martin Schneider Feb 05 '16 at 06:15
Your regex won't work, just try using it. You'd be better off going with `String.split()` first and then matching against each part. – Tim Biegeleisen Feb 05 '16 at 06:15
I still don't get it: http://rubular.com/r/OGxKqzua4s matches all the OP wants. Which are the cases where it does not work? – Martin Schneider Feb 05 '16 at 06:18
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If you are sure, then post a working snippet of Java code so that the OP may test it. – Tim Biegeleisen Feb 05 '16 at 06:19
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I added a sample program – Martin Schneider Feb 05 '16 at 06:28
It looks better now. So you are looping over the string and finding matches. I think the initial confusion was because you made it look like you were using a single flat regex for everything. – Tim Biegeleisen Feb 05 '16 at 06:30

score 0 · Answer 2 · answered Feb 05 '16 at 05:51

0

The regex you are probably looking for is [A-a][0-9]{1,2}.

So in Java,

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


String test = "A1=CA2=BOA2=RA4=OA11=O";
Matcher m = Pattern.compile("[A-a][0-9]{1,2}").matcher(test);
while (m.find()) {
    System.out.print(m.group(0)+",");
}

answered Feb 05 '16 at 05:51

intboolstring

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@RahulBhawar. You are most definitely right! But you didn't bother to read the question to see that that isn't a use case. Furthermore, the OPs broken regex has the intent to match numbers `1-100`. – intboolstring Feb 05 '16 at 06:30

Tim Biegeleisen · Answer 3 · 2016-02-05T05:55:29.580

0

String test = "A1=CA2=BOA2=RA4=OA11=O";
String[] parts = test.split("=");
String[] output = new String[parts.length];
for (int i=0; i < parts.length; ++i) {
    output[i] = parts[i].replaceAll("^.*(A\\d*)$", "$1");
    System.out.println(parts[i] + " becomes " + output[i]);
}

Output:

A1 becomes A1
CA2 becomes A2
BOA2 becomes A2
RA4 becomes A4
OA11 becomes A11
O becomes O

edited Feb 05 '16 at 05:55

answered Feb 05 '16 at 05:51

Tim Biegeleisen

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"OA11 becomes OA11" - Shouldn't `OA11` go to `A11`? – intboolstring Feb 05 '16 at 05:54
@intboolstring Good call. You posted so quickly, I had no time for thorough testing ^ ^ – Tim Biegeleisen Feb 05 '16 at 05:55
I can not split using '=' because my string contains multiple times '='. For example "A1=C,R=25A2=BOA2=RA4=OA11=O"; – Shiladittya Chakraborty Feb 05 '16 at 05:58
@ShiladittyaChakraborty I think you are confused on how String.split() works. It will split up the string using all = signs, no matter how many appear. Please test my code to see for yourself. You should be able to just cut and paste it. – Tim Biegeleisen Feb 05 '16 at 06:08

Extract Particular String from string in java

3 Answers3