Reverse capture group combined with forward capture group

Question

Reverse capture group combined with forward capture group

Does the title not just sum it up? I'm attempting to gather groups and merge them together.

Here's the text in question:

GPX 10.802.123/3843 1 - IDENTIFIER 48

And this is what I desire as output:

IDENTIFIER 10.802.123/3843-48

So, just to be clear, I aim to capture a group before and after a specific word, then concatenate the two using only regex. Feasible?

I've managed to extract 48 in the following manner:

var text = GPX 10.802.123/3843 1 - IDENTIFIER 48
var reg = new RegExp('IDENTIFIER' + '.*?(\\d\\S*)', 'i');
var match = reg.exec(text);

Output:

Can it really be done?

My offer stands at 200 points.

javascript regex

Answer 1

Answer №1

Prior to extracting the desired groups, it is crucial to clearly define them. For instance, if you specify the group before the target word as consisting of four or more non-whitespace characters, and the group after the word as comprising one or more non-whitespace characters, you can utilize the subsequent regular expression.

var re = new RegExp('(\\S{4,})\\s+(?:\\S{1,3}\\s+)*?' + word + '.*?(\\S+)', 'i');
var groups = re.exec(text);
if (groups !== null) {
   var result = groups[1] + groups[2];
}

Lets delve into the inner workings of the regular expression. Take note that we need to escape the backslashes since we are crafting a regular expression within a string.

(\\S{4,}) captures a segment comprised of four or more non-whitespace characters
\\s+ matches one or more whitespace characters
(?: signifies the commencement of a non-capturing group
\\S{1,3} matches one to three non-whitespace characters
\\s+ matches one or more whitespace characters
)*? makes the non-capturing group match zero or more times, with minimal occurrences
word corresponds to the content stored in the variable word during compilation of the regular expression
.*? matches any character zero or more times, with minimal occurrences
(\\S+) captures one or more non-whitespace characters
the 'i' flag renders this a case-insensitive regular expression

Note how our utilization of the ? modifier enables us to capture the nearest groups preceding and succeeding the word.

To globally match the regular expression in the text, append the g flag. The following snippet illustrates how to extract all occurrences.

function forward_and_backward(word, text) {
  var re = new RegExp('(\\S{4,})\\s+(?:\\S{1,3}\\s+)*?' + word + '.*?(\\S+)', 'ig');
  // Find all matches and construct an array of results.
  var results = [];
  while (true) {
    var groups = re.exec(text);
    if (groups === null) {
      return results;
    }
    var result = groups[1] + groups[2];
    results.push(result);
  }
}

var sampleText = "  GPX 10.802.123/3843- 1 -- IDENTIFIER 48   A BC 444.2345.1.1/99x 28 - - Identifier 580 X Y Z 9.22.16.1043/73+ 0  ***  identifier 6800";

results = forward_and_backward('IDENTIFIER', sampleText);
for (var i = 0; i < results.length; ++i) { 
  document.write('result ' + i + ': "' + results[i] + '"<br><br>');
}

body {
  font-family: monospace;
}

Answer 2

Prior to extracting the desired groups, it is crucial to clearly define them. For instance, if you specify the group before the target word as consisting of four or more non-whitespace characters, and the group after the word as comprising one or more non-whitespace characters, you can utilize the subsequent regular expression.

var re = new RegExp('(\\S{4,})\\s+(?:\\S{1,3}\\s+)*?' + word + '.*?(\\S+)', 'i');
var groups = re.exec(text);
if (groups !== null) {
   var result = groups[1] + groups[2];
}

Lets delve into the inner workings of the regular expression. Take note that we need to escape the backslashes since we are crafting a regular expression within a string.

(\\S{4,}) captures a segment comprised of four or more non-whitespace characters
\\s+ matches one or more whitespace characters
(?: signifies the commencement of a non-capturing group
\\S{1,3} matches one to three non-whitespace characters
\\s+ matches one or more whitespace characters
)*? makes the non-capturing group match zero or more times, with minimal occurrences
word corresponds to the content stored in the variable word during compilation of the regular expression
.*? matches any character zero or more times, with minimal occurrences
(\\S+) captures one or more non-whitespace characters
the 'i' flag renders this a case-insensitive regular expression

Note how our utilization of the ? modifier enables us to capture the nearest groups preceding and succeeding the word.

To globally match the regular expression in the text, append the g flag. The following snippet illustrates how to extract all occurrences.

function forward_and_backward(word, text) {
  var re = new RegExp('(\\S{4,})\\s+(?:\\S{1,3}\\s+)*?' + word + '.*?(\\S+)', 'ig');
  // Find all matches and construct an array of results.
  var results = [];
  while (true) {
    var groups = re.exec(text);
    if (groups === null) {
      return results;
    }
    var result = groups[1] + groups[2];
    results.push(result);
  }
}

var sampleText = "  GPX 10.802.123/3843- 1 -- IDENTIFIER 48   A BC 444.2345.1.1/99x 28 - - Identifier 580 X Y Z 9.22.16.1043/73+ 0  ***  identifier 6800";

results = forward_and_backward('IDENTIFIER', sampleText);
for (var i = 0; i < results.length; ++i) { 
  document.write('result ' + i + ': "' + results[i] + '"<br><br>');
}

body {
  font-family: monospace;
}

Answer 3

Answer №2

Here is a code snippet for extracting specific information from text:

let inputText = 'GPX 10.802.123/3843 1 - IDENTIFIER 48';
let regexPattern = /GPX\s+(.+?) \d .*?(IDENTIFIER).*?(\d\S*)/i;
let resultArray = regexPattern.exec(inputText);

let finalOutput = resultArray[2] + ' ' + resultArray[1] + '-' + resultArray[3];
//=> "IDENTIFIER 10.802.123/3843-48"

Answer 4

Here is a code snippet for extracting specific information from text:

let inputText = 'GPX 10.802.123/3843 1 - IDENTIFIER 48';
let regexPattern = /GPX\s+(.+?) \d .*?(IDENTIFIER).*?(\d\S*)/i;
let resultArray = regexPattern.exec(inputText);

let finalOutput = resultArray[2] + ' ' + resultArray[1] + '-' + resultArray[3];
//=> "IDENTIFIER 10.802.123/3843-48"

Answer 5

Answer №3

The replace function can be used to achieve this task.

var string = 'GPX 10.802.123/3843 1 - IDENTIFIER 48';
string.replace(/.*?(\S+)\s+\d+\s*-\s*(IDENTIFIER)\s*(\d+).*/, "$2 $1-$3");

Answer 6

The replace function can be used to achieve this task.

var string = 'GPX 10.802.123/3843 1 - IDENTIFIER 48';
string.replace(/.*?(\S+)\s+\d+\s*-\s*(IDENTIFIER)\s*(\d+).*/, "$2 $1-$3");

Answer 7

Answer №4

^\s*\S+\s*\b(\d+(?:[./]\d+)+)\b.*?-.*?\b(\S+)\b\s*(\d+)\s*$

This regex pattern can be used to match specific text patterns in a string. When replaced with $2 $1-$3, it captures and rearranges the matched groups accordingly. You can test this regex pattern using the demo provided here.

var re = /^\s*\S+\s*\b(\d+(?:[.\/]\d+)+)\b.*?-.*?\b(\S+)\b\s*(\d+)\s*$/gm; 
var str = 'GPX 10.802.123/3843 1 - IDENTIFIER 48';
var subst = '$2 $1-$3'; 

var result = str.replace(re, subst);

Answer 8

^\s*\S+\s*\b(\d+(?:[./]\d+)+)\b.*?-.*?\b(\S+)\b\s*(\d+)\s*$

This regex pattern can be used to match specific text patterns in a string. When replaced with $2 $1-$3, it captures and rearranges the matched groups accordingly. You can test this regex pattern using the demo provided here.

var re = /^\s*\S+\s*\b(\d+(?:[.\/]\d+)+)\b.*?-.*?\b(\S+)\b\s*(\d+)\s*$/gm; 
var str = 'GPX 10.802.123/3843 1 - IDENTIFIER 48';
var subst = '$2 $1-$3'; 

var result = str.replace(re, subst);

Answer 9

Answer №5

Utilizing the 'split' method is another approach:

let textPhrase = 'GPX 10.802.123/3843 1 - IDENTIFIER 48';

let sections = textPhrase.split(/\s+/);

if (sections[4] == 'IDENTIFIER') {
    let finalResult = sections[4] + ' ' + sections[1] + '-' + sections[5];
    console.log(finalResult);
}

Answer 10

Utilizing the 'split' method is another approach:

let textPhrase = 'GPX 10.802.123/3843 1 - IDENTIFIER 48';

let sections = textPhrase.split(/\s+/);

if (sections[4] == 'IDENTIFIER') {
    let finalResult = sections[4] + ' ' + sections[1] + '-' + sections[5];
    console.log(finalResult);
}

Reverse capture group combined with forward capture group

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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