CODEWITHSUNDEEP
flutterdart
Sukhchain Singh
Sukhchain Singh

Reputation: 844

How to get substring between two strings in DART?

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

Upvotes: 37

Views: 68307

Answers (7)

Karue Benson Karue
Karue Benson Karue

Reputation: 1026

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

  print(getSringBetween(str, start, end));
  //OUT PUTS: brown fox jumps
}

String getSringBetween(str, start, end) {
  return str.split(start).last.split(end)[0].trim();
}

Upvotes: 1

Feshibaba
Feshibaba

Reputation: 101

For future researchers: To start form the beginning of a string to a specific symbol or character;

Using substring and indexOf which is faster than regExp do this:

void main() {
  const str = "Cars/Horses";

  final endIndex = str.indexOf("/", 0);

  print(str.substring(0, endIndex)); // Cars
}

This might just help someone

Upvotes: 3

Oliver Dixon
Oliver Dixon

Reputation: 7405

The substring functionality isn't that great, and will throw errors for strings above the "end" value.

To make it simpler user this custom function that doesn't thrown an error, instead using the max length.

String substring(String original, {required int start, int? end}) {
  if (end == null) {
    return original.substring(start);
  }
  if (original.length < end) {
    return original.substring(start, original.length);
  }
  return original.substring(start, end);
}

Upvotes: 1

CopsOnRoad
CopsOnRoad

Reputation: 267474

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();

Upvotes: 5

R&#233;mi Rousselet
R&#233;mi Rousselet

Reputation: 276997

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.

Upvotes: 79

Spatz
Spatz

Reputation: 20118

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));
}

Upvotes: 10

bimsina
bimsina

Reputation: 444

You can do that with the help of regex. Create a function that will return the regex matches as

Iterable<String> _allStringMatches(String text, RegExp regExp) => 
regExp.allMatches(text).map((m) => m.group(0));

And then define your regex as RegExp(r"[quick ]{1}.*[ over]{1}"))

Upvotes: 2

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