What are various string functions in Dart?

Dart - Interview Questions

Dart provides several built-in string functions that you can use to manipulate and work with strings. Here are some commonly used string functions in Dart:

1. length : The `length` property returns the number of characters in a string.

   String str = 'Hello, Dart!';
   print(str.length); // Output: 13â€‹

2. toUpperCase() / toLowerCase() : These methods return a new string with all characters converted to uppercase or lowercase, respectively.

   String str = 'Hello, Dart!';
   print(str.toUpperCase()); // Output: HELLO, DART!
   print(str.toLowerCase()); // Output: hello, dart!â€‹

3. trim() : The `trim()` method removes leading and trailing whitespace characters from a string.

   String str = '   Hello, Dart!   ';
   print(str.trim()); // Output: Hello, Dart!â€‹

4. split() : The `split()` method splits a string into a list of substrings based on a specified delimiter.

   String str = 'apple,banana,orange';
   List fruits = str.split(',');
   print(fruits); // Output: [apple, banana, orange]â€‹

5. substring() : The `substring()` method returns a new string that is a substring of the original string, starting at a specified index and optionally ending at another index.

   String str = 'Hello, Dart!';
   print(str.substring(7)); // Output: Dart!
   print(str.substring(0, 5)); // Output: Helloâ€‹

6. indexOf() / lastIndexOf() : These methods return the index of the first/last occurrence of a specified substring within a string. If the substring is not found, they return -1.

   String str = 'Hello, Dart!';
   print(str.indexOf('Dart')); // Output: 7
   print(str.lastIndexOf('l')); // Output: 10â€‹

7. startsWith() / endsWith() : These methods check if a string starts or ends with a specified substring, returning a boolean result.

   String str = 'Hello, Dart!';
   print(str.startsWith('Hello')); // Output: true
   print(str.endsWith('!')); // Output: trueâ€‹

8. contains() : The `contains()` method checks if a string contains a specified substring, returning a boolean result.

   String str = 'Hello, Dart!';
   print(str.contains('Dart')); // Output: true
   print(str.contains('Python')); // Output: falseâ€‹

9. replace() : The `replace()` method replaces all occurrences of a specified substring with another substring.

   String str = 'Hello, Dart!';
   String newStr = str.replaceFirst('Dart', 'World');
   print(newStr); // Output: Hello, World!â€‹