Analyzing an ArrayList Object

boolean contains(Object o)

This method returns true if Object o is found in the ArrayList; false otherwise.

Your Turn

Let's try it in the Java Playground.

• Predict the output of the code.
• Run the code to determine if your prediction is correct.
• Update the found to look for "David". Predict the output of the code and run it to determine if your prediction is correct.

int indexOf(Object o)

This method return the index of the first occurrence of Object o if it exists. If the ArrayList does not contain this value, the method returns -1.

Your Turn

Let's try it in the Java Playground.

• Predict the output of the code.
• Run the code to determine if your prediction is correct.
• Write code to obtain the index for "David". Predict the output of the code and run it to determine if your prediction is correct.
• Write code to obtain the index for "Susie". Predict the output of the code and run it to determine if your prediction is correct.

boolean isEmpty()

The method returns true if there are no elements in the ArrayList and false otherwise.

Your Turn

Let's try it in the Java Playground.

• Predict the output of the code.
• Run the code to determine if your prediction is correct.

Complete List of ArrayList Tutorials

• Learn: Constructing an ArrayList Object
• Learn: Adding Values to an ArrayList Object
• Learn: Accessing and Removing Values from an ArrayList Object
• Learn: Changing Values in an ArrayList Object
• Learn: Analyzing an ArrayList Object
• Learn: Iterating Over an ArrayList Object

Resources

• Practice: Evaluating Code Segments with ArrayList Objects
• Practice: Write Code Segments that Use ArrayList Objects