In Dart, you can split a string into a list of substrings using the <code>split()</code> method, and you can join a list of strings into a single string using the <code>join()</code> method.
Example:
<pre><code class="lang-dart">void main() {
 List&lt;String&gt; parts = ["Hello", "World!"];

 String str = "Hello, Jeet";

 print(str.split(','));
 print(parts.join(',')); // Output: Hello, World!
}
</code></pre>

In Dart, you can split a string into a list of substrings using the `split()` method, and you can join a list of strings into a single string using the `join()` method.

Example:

```dart
void main() {
 List<String> parts = ["Hello", "World!"];

 String str = "Hello, Jeet";

 print(str.split(','));
 print(parts.join(',')); // Output: Hello, World!
}
```

Split & join String in dart