Java regex to create map from multi line string

Question

I am trying to create a Map from a multi-line String with various patterns. For example, considering the following String:

:20:94001142322029214336
    1234
    6789
:86F:/PG/1L123
:25|11298666
:28G::20/1345
      xyz

My patterns are like:

starting : OR :: OR | OR || and ending with : OR :: OR | OR || I am trying to create a map as follows:

Key   = 20
Value = 94001142322029214336
        1234
        6789  

Key =   86F
Value = /PG/1L

Key = 25 
Value = 11298666

Key  = 28G

Value = 20/1 xyz

The value can be multi line so i need all the lines from value to be part of my map value for that key.

Could you please help me to create the Java regex or any other solution that can help me to create this map?

You're trying to create a Map with the same blank key for different values. That's not going to work.... — lreeder
– lreeder, Commented Mar 23, 2014 at 3:22
it is not confusing. He has multiline text. Keys are enclosed within combination of : and | and values may or may not be multiline text. — Nishant
– Nishant, Commented Mar 23, 2014 at 3:26

aliteralmind · Accepted Answer · 2014-03-23 05:12:14Z

1

Split the string with

String[] lineElements = line.split("(?:\\:|\\|){1,2}");

Either there's only one element, meaning there's no key (in this case you'll need to use the most-recent one, which you'll need to keep track of), or there are three elements:

Always empty
The key
The value

To allow for the reverse of this process (to recreate the input file, based on the already-parsed data), you could store each line's data into its own object, such as

public class WhateverDataObject  {
   public final String key;
   public final String value;
   public WhateverDataObject(String key, String value)  {
      this.key = key;
      this.value = value;
   }
   public String toString()  {
      ":" + key + ":" + value;
   }
}

Then output each object's toString().

If you also need the delimiters to be exactly as they were, that's a lot more work, as you'll need to pre-analyze each line, and add those elements to the DataObject, including its toString().

edited Mar 23, 2014 at 5:12

answered Mar 23, 2014 at 3:28

aliteralmind

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6 Comments

Pramod Over a year ago

String can start with | or || or :: as well, so will this regex give me correct values? ::20:1234 ||20:|1234 etc.

aliteralmind Over a year ago

Yes, I mention that in my answer: The consequence is that the first element in the three-element array (when there is a key) will always be empty.

Pramod Over a year ago

Thanks a ton for the quick help...I have another requirements to replace the value in the similar string for specific tag, the tag may repeat many times, so want to replace specific occurrence so can't use replace or replaceAll and after replacing the tag value i have to write the entire string again with delimiters, for example :20:1234\n:28G::xyz\n|20:3456\n:29C:pqr\n:20|9876 so 3456 needs to be replaced from tag 20 for second occurrence with 5678 so the final string should look like :20:1234\n:28G::xyz\n|20:5678\n:29C:pqr\n:20|9876 any tips on how to do it..?

aliteralmind Over a year ago

I'll answer you here, but this really should have either been in your original question, or posted as a new question. Give me a minute, and I'll update my answer.

Pramod Over a year ago

Sorry for not adding it into my original question, i was planning to create new question but thought will post it here to get quick answer :)

|

Dexters · Accepted Answer · 2014-03-23 04:17:57Z

0

you can try and use this ..

Replace all possible Key identifiers with just one.. then split using them..

import java.util.Arrays;
import java.util.HashSet;

public class HelloWorld{

     public static void main(String []args)
     {
        String input = ":20:94001142322029214336\n1234\n6789\n:86F|/PG/1L123\n:25||11298666\\:28G::20/1345\nxyz";
         System.out.println(input+"\n\n");

        input=input.replace("::",":");
        input=input.replace("||",":");
        input=input.replace("|",":");
         System.out.println(input+"\n\n");

        String words[] = input.split(":");
        for(int index = 1;index<words.length;index++)
        {
             System.out.println("Key = "+words[index]+"\nValue = "+words[++index]);
        }
     }

answered Mar 23, 2014 at 4:17

Dexters

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1 Comment

aliteralmind Over a year ago

Just style, but I'd choose a single regex replacement: Find what="(:|\|){1,2}", Replace with=":". (The character class [:|] would be inappropriate as it would replace invalid separators, such as "|:".)

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