CODEWITHSUNDEEP
dart
user1869518
user1869518

Reputation:

Trimming whitespace in Dart strings from beginning or end

I am very new to Dart and am trying to get some sense of the basic libraries. For strings, there is a trim() function provided. This is good, but are there no obvious ways to trim whitespace only at the beginning or only at the end of a string? I cannot find them.Thank you.

Upvotes: 8

Views: 3388

Answers (3)

Justin Fagnani
Justin Fagnani

Reputation: 11171

We just added trimLeft and trimRight to Quiver today, though it turns out that they are also being added to String in future SDK release. You can use Quiver today though.

The difference between these implementations and the Regex-based solution is that the definition of whitespace is the same as String.trim. Regex's recognize fewer whitespace characters.

http://pub.dartlang.org/packages/quiver

Upvotes: 1

Lukas Renggli
Lukas Renggli

Reputation: 8947

The library MoreDart has some Guava inspired helpers that allow you to efficiently trim strings from beginning, end, or both:

import 'package:more/char_matcher.dart';

...

var whitespace = new CharMatcher.whitespace();    // what to trim

whitespace.trimFrom(input);   // trim from beginning and end
whitespace.trimLeadingFrom(input);   // trim from beginning
whitespace.trimTrailingFrom(input);   // trim from end

Upvotes: 1

Shailen Tuli
Shailen Tuli

Reputation: 14171

There are no specific methods for trimming only leading or trailing whitespace. But it is quite easy to implement them:

/// trims leading whitespace
String ltrim(String str) {
  return str.replaceFirst(new RegExp(r"^\s+"), "");
}

/// trims trailing whitespace
String rtrim(String str) {
  return str.replaceFirst(new RegExp(r"\s+$"), "");
}

Upvotes: 13

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