What comprises the Dart Characters Library?

These can be explained as follows:

String manipulation: Functions to modify strings, which include concatenation, splitting, and replacing substrings.
Substring extraction: Tools to extract specific portions of a string based on indexes or patterns.
Character handling: Methods for handling individual characters in strings, such as accessing, modifying, or checking properties of characters.
Unicode support: Can handle Unicode characters, enabling the use of characters from different languages.
Regular expression: Support for pattern matching using regular expressions, allowing for complex string search and manipulation.
Encoding and decoding: Functions to convert strings to various encodings and decode them back.
Sorting: Algorithms to sort strings or characters, providing order based on specific criteria.
Character information: Access to character-related information, such as character codes, properties, or metadata.

Let’s explore how these can be implemented in code.

Example

A coding example of this library is provided below. Below the code, the code and the various functions are explained.

void main() {
  String text = "Hello, World!"; //Initialization
  print("Message: $text");
  String upperCaseMessage = text.toUpperCase(); //String manipulation
  String lowerCaseMessage = text.toLowerCase();
  print("Uppercase: $upperCaseMessage");
  print("Lowercase: $lowerCaseMessage");
  String substring = text.substring(7); //Substring extraction
  print("Substring from index 7: $substring");
  String name = "Dart";
  print("First character of Dart: ${name[0]}"); //Character handling
  String emoji = '\u{1F480}'; //Unicode support
  print("Unicode Grinning Face Emoji: $emoji");
  String email = "example@email.com";
  bool isEmailValid = RegExp(r'^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$').hasMatch(email); //Regular expressions
  print("Email validity: $isEmailValid");
  String encodedText = Uri.encodeComponent(text); //Encoding
  print("Encoded text: $encodedText");
  String decodedText = Uri.decodeComponent(encodedText); //Decoding
  print("Decoded text: $decodedText");
  List<String> words = ['banana', 'apple', 'orange', 'grape'];
  words.sort(); //Sorting
  print("Sorted words: $words");
  String char = 'A';
  print("Unicode value of 'A': ${char.codeUnitAt(0)}"); //Unicode support
}

The code is explained below:

Lines 2–3: Initialize a variable text with the value Hello, World!.
Lines 5–8: This is string manipulation. Converting the string to uppercase and lowercase and printing the results. This is done through the toUpperCase() and toLowerCase().
Lines 10–11: This is substring extraction. Extract a substring starting from index 7 till the end of the string and printing it.
Lines 13–14: This is character handling. Accessing the first character of the string and printing it.
Lines 16–17: This is Unicode support. Storing a Unicode character representing the skull emoji in the emoji variable.
Lines 19–21: This is a use of regular expressions. Validating an email using regular expressions and storing the result in isEmailValid.
Lines 23–26: This is encoding and decoding. Encoding and decoding a text using Uri's encoding and decoding methods.
Lines 28–30: This is an example of sorting. This sorts a list of strings alphabetically with the sort() function and prints it.
Lines 32–33: Accessing the Unicode value of A and printing it.

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