How to get substring between two strings in DART?

Question

How can i achieve similar solution to: How to get a substring between two strings in PHP? but in DART

For example I have a String:
String data = "the quick brown fox jumps over the lazy dog"
I have two other Strings: quick and over
I want the data inside these two Strings and expecting result:
brown fox jumps

Solution 1

You can use String.indexOf combined with String.substring:

void main() {
  const str = "the quick brown fox jumps over the lazy dog";
  const start = "quick";
  const end = "over";

  final startIndex = str.indexOf(start);
  final endIndex = str.indexOf(end, startIndex + start.length);

  print(str.substring(startIndex + start.length, endIndex)); // brown fox jumps
}

Note also that the startIndex is inclusive, while the endIndex is exclusive.

Solution 2

I love regexp with lookbehind (?<...) and lookahead (?=...):

void main() {
  var re = RegExp(r'(?<=quick)(.*)(?=over)');
  String data = "the quick brown fox jumps over the lazy dog";
  var match = re.firstMatch(data);
  if (match != null) print(match.group(0));
}

Solution 3

final str = 'the quick brown fox jumps over the lazy dog';
final start = 'quick';
final end = 'over';

final startIndex = str.indexOf(start);
final endIndex = str.indexOf(end);
final result = str.substring(startIndex + start.length, endIndex).trim();

Comments

[Ajil O.]

I was almost about to post an answer with RegExp. But this one's better

[Sukhchain Singh]

Thank you, my string was very large so Rémi Rousselet's answer didn't helped. This one worked like a charm.

[Sukhchain Singh]

My String is actually unformatted HTML and is very long. substring method failed with RangeError. So, @Sergey Solodukhin's answer worked for me. This one is awesome for smaller Strings. Thank you.

[Rémi Rousselet]

@SukhchainSingh it was a bug. I've just fixed it

[Sukhchain Singh]

@RémiRousselet Thank you, it worked. It's lot faster than regexp as expected :)

[Spatz]

What's about real data? Word order may change "the over quick brown fox jumps the lazy dog" or one keyword may be absent.

[Sukhchain Singh]

@SergeySolodukhin No it's not absent in my case and order will be not changed too.