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This deck focuses on Arraylist Traversals, giving you a quick way to review the definitions, rules, and examples that matter most for AP Computer Science a.
AP Computer Science a Flashcards: Arraylist Traversals
Study Arraylist Traversals in AP Computer Science a with focused flashcards that help you recognize the idea, recall the key rule, and apply it in practice-style prompts.
AP Computer Science a
Arraylist Traversals
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Find the syntax to initialize an empty ArrayList of integers.
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ANSWER
ArrayList list = new ArrayList<>();. Creates new empty ArrayList with Integer type parameter.
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Flashcard 1: Find the syntax to initialize an empty ArrayList of integers.
Answer: ArrayList list = new ArrayList<>();. Creates new empty ArrayList with Integer type parameter.
Flashcard 2: Identify the index of the first element in an ArrayList.
Answer:
Flashcard 3: State the method to sort elements in an ArrayList using natural ordering.
Answer: Collections.sort(arrayList). Sorts elements using their natural comparison order.
Flashcard 4: What loop structure uses an iterator to traverse an ArrayList?
Answer: Iterator loop. Uses Iterator object for controlled sequential access.
Flashcard 5: What loop structure uses an iterator to traverse an ArrayList?
Answer: Iterator loop. Uses Iterator object for controlled sequential access.
Flashcard 6: Identify a method to get the size of an ArrayList.
Answer: ArrayList.size(). Returns number of elements currently stored in the list.
Flashcard 7: What is the return type of ArrayList.size()?
Answer: int. Returns integer count of elements in the ArrayList.
Flashcard 8: Write the for-each loop syntax to traverse an ArrayList of integers.
Answer: for (Integer num : arrayList) { }. Enhanced for loop iterates through each Integer in the list.
Flashcard 9: Choose the method to convert an ArrayList to an array.
Answer: ArrayList.toArray(). Converts ArrayList to standard array format.
Flashcard 10: Identify the method to obtain an iterator for an ArrayList.
Answer: ArrayList.iterator(). Returns Iterator object for traversing the ArrayList.
Flashcard 11: Identify the method to retain only elements in an ArrayList that are contained in another collection.
Answer: ArrayList.retainAll(collection). Keeps only elements present in both collections.
Flashcard 12: Write the for-each loop syntax to traverse an ArrayList of integers.
Answer: for (Integer num : arrayList) { }. Enhanced for loop iterates through each Integer in the list.
Flashcard 13: What exception is thrown when accessing an invalid index in an ArrayList?
Answer: IndexOutOfBoundsException. Runtime exception for accessing non-existent index positions.
Flashcard 14: What is the return type of ArrayList.size()?
Answer: int. Returns integer count of elements in the ArrayList.
Flashcard 15: Identify the method to add an element to the end of an ArrayList.
Answer: ArrayList.add(element). Appends element to the end of the list.
Flashcard 16: What is the time complexity of removing an element from the beginning of an ArrayList?
Answer: O(n). Requires shifting all subsequent elements leftward.
Flashcard 17: State the method to clear all elements from an ArrayList.
Answer: ArrayList.clear(). Removes all elements, making the ArrayList empty.
Flashcard 18: What type of loop is commonly used to traverse an ArrayList?
Answer: For-each loop. Enhanced for loop simplifies iteration without index management.
Flashcard 19: Choose the method to add an element at a specific index in an ArrayList.
Answer: ArrayList.add(index, element). Inserts element at specified position, shifting existing elements.
Flashcard 20: Choose the method to replace all elements in an ArrayList with specified elements.
Answer: ArrayList.replaceAll(unaryOperator). Applies function to transform each element in place.
Flashcard 21: What is the purpose of traversing an ArrayList?
Answer: To access each element in the ArrayList. Allows examination or processing of every element sequentially.
Flashcard 22: Given an ArrayList of strings, write a loop to print each element.
Answer: for (String s : arrayList) { System.out.println(s); }. Enhanced for loop prints each string element sequentially.
Flashcard 23: State the method to remove the first occurrence of an element from an ArrayList.
Answer: ArrayList.remove(element). Searches and removes first matching element found.
Flashcard 24: Find the syntax to initialize an empty ArrayList of integers.
Answer: ArrayList list = new ArrayList<>();. Creates new empty ArrayList with Integer type parameter.
Flashcard 25: Identify the keyword to break out of a loop early.
Answer: break. Immediately exits loop when condition is met.
Flashcard 26: Identify a method to get the size of an ArrayList.
Answer: ArrayList.size(). Returns number of elements currently stored in the list.
Flashcard 27: Find the index of the last element in an ArrayList of size n.
Answer: n−1. Last index equals size minus one due to zero-based indexing.
Flashcard 28: What is a common error when accessing elements during an ArrayList traversal?
Answer: ConcurrentModificationException. Thrown when modifying ArrayList during iteration.
Flashcard 29: Which method retrieves an element from an ArrayList at a specific index?
Answer: ArrayList.get(index). Returns element at specified position without removing it.
Flashcard 30: Write the syntax to traverse an ArrayList using an iterator.
Answer: while (iterator.hasNext()) { iterator.next(); }. Uses iterator methods to safely traverse elements.
Flashcard 31: State the method to sort elements in an ArrayList using natural ordering.
Answer: Collections.sort(arrayList). Sorts elements using their natural comparison order.
Flashcard 32: Identify the method to add all elements from one ArrayList to another.
Answer: ArrayList.addAll(collection). Appends all elements from source collection.
Flashcard 33: State the method to find the last index of an element in an ArrayList.
Answer: ArrayList.lastIndexOf(element). Returns highest index where element appears.
Flashcard 34: Which method retrieves an element from an ArrayList at a specific index?
Answer: ArrayList.get(index). Returns element at specified position without removing it.
Flashcard 35: Choose the method to replace all elements in an ArrayList with specified elements.
Answer: ArrayList.replaceAll(unaryOperator). Applies function to transform each element in place.
Flashcard 36: Which method replaces an element at a specific index in an ArrayList?
Answer: ArrayList.set(index, element). Updates element at specified index position.
Flashcard 37: Identify the keyword to break out of a loop early.
Answer: break. Immediately exits loop when condition is met.
Flashcard 38: What is the time complexity of removing an element from the beginning of an ArrayList?
Answer: O(n). Requires shifting all subsequent elements leftward.
Flashcard 39: Check if an ArrayList contains a specific element.
Answer: ArrayList.contains(element). Returns boolean indicating element presence in the list.
Flashcard 40: Identify the index of the first element in an ArrayList.
Answer:
Flashcard 41: What is the purpose of traversing an ArrayList?
Answer: To access each element in the ArrayList. Allows examination or processing of every element sequentially.
Flashcard 42: What method of Iterator checks for more elements?
Answer: Iterator.hasNext(). Returns true if more elements remain to iterate.
Flashcard 43: What is the time complexity of accessing an element by index in an ArrayList?
Answer: O(1). Direct array access provides constant time retrieval.
Flashcard 44: What is the time complexity of accessing an element by index in an ArrayList?
Answer: O(1). Direct array access provides constant time retrieval.
Flashcard 45: Identify the method to add an element to the end of an ArrayList.
Answer: ArrayList.add(element). Appends element to the end of the list.
Flashcard 46: What is the return type of ArrayList.get(index)?
Answer: Object or specified type. Returns the generic type or Object if unspecified.
Flashcard 47: Find the syntax to declare an ArrayList of strings with initial capacity.
Answer: ArrayList list = new ArrayList<>(capacity);. Pre-allocates memory for specified number of elements.
Flashcard 48: What is the time complexity of adding an element at the end of an ArrayList?
Answer: O(1). Appending to end requires no element shifting.
Flashcard 49: What method checks if two ArrayLists contain the same elements in the same order?
Answer: ArrayList.equals(object). Compares both content and order of elements.
Flashcard 50: What is the time complexity of adding an element at the end of an ArrayList?
Answer: O(1). Appending to end requires no element shifting.
Flashcard 51: What exception is thrown when accessing an invalid index in an ArrayList?
Answer: IndexOutOfBoundsException. Runtime exception for accessing non-existent index positions.
Flashcard 52: What method of Iterator checks for more elements?
Answer: Iterator.hasNext(). Returns true if more elements remain to iterate.
Flashcard 53: State the method to find the last index of an element in an ArrayList.
Answer: ArrayList.lastIndexOf(element). Returns highest index where element appears.
Flashcard 54: Given an ArrayList of strings, write a loop to print each element.
Answer: for (String s : arrayList) { System.out.println(s); }. Enhanced for loop prints each string element sequentially.
Flashcard 55: Identify the method to obtain an iterator for an ArrayList.
Answer: ArrayList.iterator(). Returns Iterator object for traversing the ArrayList.
Flashcard 56: Identify the method to check if an ArrayList is empty.
Answer: ArrayList.isEmpty(). Returns boolean indicating if size equals zero.
Flashcard 57: Identify the method to remove an element by index from an ArrayList.
Answer: ArrayList.remove(index). Removes element at specified position and returns it.
Flashcard 58: What is a common error when accessing elements during an ArrayList traversal?
Answer: ConcurrentModificationException. Thrown when modifying ArrayList during iteration.
Flashcard 59: What type of loop is commonly used to traverse an ArrayList?
Answer: For-each loop. Enhanced for loop simplifies iteration without index management.
Flashcard 60: What is the return type of ArrayList.get(index)?
Answer: Object or specified type. Returns the generic type or Object if unspecified.
Flashcard 61: State the method to remove the first occurrence of an element from an ArrayList.
Answer: ArrayList.remove(element). Searches and removes first matching element found.
Flashcard 62: What is the time complexity of iterating over an ArrayList using a for-each loop?
Answer: O(n). Must visit each element once for complete traversal.
Flashcard 63: Identify the method to remove an element by index from an ArrayList.
Answer: ArrayList.remove(index). Removes element at specified position and returns it.
Flashcard 64: What method checks if two ArrayLists contain the same elements in the same order?
Answer: ArrayList.equals(object). Compares both content and order of elements.
Flashcard 65: Which method replaces an element at a specific index in an ArrayList?
Answer: ArrayList.set(index, element). Updates element at specified index position.
Flashcard 66: Write the syntax to traverse an ArrayList using an iterator.
Answer: while (iterator.hasNext()) { iterator.next(); }. Uses iterator methods to safely traverse elements.
Flashcard 67: What is the purpose of traversing an ArrayList using an enhanced for loop?
Answer: To simplify iteration over elements. Enhanced for loop provides cleaner, safer iteration.
Flashcard 68: Check if an ArrayList contains a specific element.
Answer: ArrayList.contains(element). Returns boolean indicating element presence in the list.
Flashcard 69: What is the purpose of traversing an ArrayList using an enhanced for loop?
Answer: To simplify iteration over elements. Enhanced for loop provides cleaner, safer iteration.
Flashcard 70: Find the index of the last element in an ArrayList of size n.
Answer: n−1. Last index equals size minus one due to zero-based indexing.
Flashcard 71: Find the syntax to declare an ArrayList of strings with initial capacity.
Answer: ArrayList list = new ArrayList<>(capacity);. Pre-allocates memory for specified number of elements.
Flashcard 72: Choose the method to convert an ArrayList to an array.
Answer: ArrayList.toArray(). Converts ArrayList to standard array format.
Flashcard 73: What is the time complexity of iterating over an ArrayList using a for-each loop?
Answer: O(n). Must visit each element once for complete traversal.
Flashcard 74: State the method to clear all elements from an ArrayList.
Answer: ArrayList.clear(). Removes all elements, making the ArrayList empty.
Flashcard 75: Identify the method to add all elements from one ArrayList to another.
Answer: ArrayList.addAll(collection). Appends all elements from source collection.
Flashcard 76: Identify the method to retain only elements in an ArrayList that are contained in another collection.
Answer: ArrayList.retainAll(collection). Keeps only elements present in both collections.
Flashcard 77: Choose the method to add an element at a specific index in an ArrayList.
Answer: ArrayList.add(index, element). Inserts element at specified position, shifting existing elements.
Flashcard 78: Identify the method to check if an ArrayList is empty.
Answer: ArrayList.isEmpty(). Returns boolean indicating if size equals zero.