List in Dart
List in Dart
About
- Lists in Dart are ordered collections of items.
- They can store elements of the same type or mixed types.
- Lists are zero-indexed, meaning the first element is at index 0.
- Dart provides various list operations and methods for manipulation.
Main Topics
-
List Creation
-
Definition: How to create and initialize lists in Dart.
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Example:
void main() { // Creating an empty list List<String> fruits = []; // Creating a list with initial values List<String> vegetables = ['Carrot', 'Potato', 'Spinach']; }
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List Operations
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Definition: Methods for adding, removing, and accessing elements in a list.
-
Example:
void main() { List<String> fruits = ['Apple', 'Banana']; // Adding an element fruits.add('Orange'); // Removing an element fruits.remove('Banana'); // Accessing elements print(fruits[0]); // Outputs: Apple }
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List Types
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Definition: Fixed-length vs. growable lists.
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Example:
void main() { // Fixed-length list List<int> fixedList = List.filled(3, 0); fixedList[0] = 1; // Growable list List<int> growableList = []; growableList.add(1); growableList.add(2); print(fixedList); // Outputs: [1, 0, 0] print(growableList); // Outputs: [1, 2] }
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List Iteration
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Definition: Techniques for looping through list elements.
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Example:
void main() { List<String> fruits = ['Apple', 'Banana', 'Orange']; // Using a for loop for (int i = 0; i < fruits.length; i++) { print(fruits[i]); } // Using forEach fruits.forEach((fruit) { print(fruit); }); }
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List Methods
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Definition: Common methods for manipulating lists such as
add()
,remove()
,insert()
, andsort()
. -
Example:
void main() { List<String> fruits = ['Apple', 'Banana', 'Orange']; // Adding an element fruits.add('Grapes'); // Removing an element fruits.remove('Banana'); // Inserting an element at a specific index fruits.insert(1, 'Blueberry'); // Sorting the list fruits.sort(); print(fruits); // Outputs: [Apple, Blueberry, Grapes, Orange] }
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How to Use
- Creating a List: Use square brackets
[]
or theList
constructor. - Accessing Elements: Use index notation (e.g.,
list[index]
) to get or set elements. - Modifying Lists: Add, remove, or change elements using list methods.
- Iterating: Use loops or methods like
forEach
to process list elements.
How It Works
- Creation: Lists can be created with initial values or as empty.
- Operations: Modify lists by accessing elements with indices and using methods for adding, removing, or updating.
- Iteration: Loop through lists using
for
,forEach
, or other iteration methods. - Types: Fixed-length lists have a set size, while growable lists can expand dynamically.
Example of List Operations:
void main() {
// Creating a growable list
List<String> fruits = ['Apple', 'Banana'];
// Adding elements
fruits.add('Orange');
// Removing an element
fruits.remove('Banana');
// Accessing elements
print(fruits[0]); // Outputs: Apple
// Iterating through the list
fruits.forEach((fruit) {
print(fruit); // Outputs: Apple, Orange
});
}
Conclusion
A List in Dart is a versatile collection that allows you to store ordered data. It supports various operations, such as accessing, modifying, adding, and removing elements, making it highly useful for scenarios where ordered data and duplicates are required.