Transcript ArrayList PPT

ArrayList
Methods tested on AP
add
 size
 get
 set
 remove
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Add
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add(int index, Object o)
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Inserts o at index in the list
ex: band.add(1, “Ringo”);
add(Object o)
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Inserts o at the end of the list
ex: band.add(“John”);
Size
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size()
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returns the number of elements in the list
return type int
Ex:
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System.out.print(“Band size: “+ band.size());
Get
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get(int index)
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returns the Object at the given index
since an Object is returned, casting is required in
order to use the Object
ex: String member = (String)band.get(1);
Set
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set(int index, Object o)
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Replaces the element at the specified position
(index) in this list with o.
ex: band.set(1, “George”); //replaces the object
at position 1 with “George”
Has a return type of Object
ex: System.out.println(band.set(3,"Bob")); //this
will print the object that Bob replaced
Remove
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remove(int index)
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Removes the element at the specified position
(index) in this list.
Returns an Object.
the Object returned is the element that was
removed
ex: band.remove(1);
ex: band.add(band.remove(1));
Other methods:
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clear()
contains(Object elem)
indexOf(Object elem)
isEmpty()
lastIndexOf(Object elem)
removeRange(int fromIndex, int toIndex)
toArray()
toString
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public String toString()
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Returns a string representation of this collection. The string
representation consists of a list of the collection's elements
in the order they are returned by its iterator, enclosed in
square brackets ("[]"). Adjacent elements are separated by
the characters ", " (comma and space). Elements are
converted to strings as by String.valueOf(Object). This
implementation creates an empty string buffer, appends a
left square bracket, and iterates over the collection
appending the string representation of each element in
turn. After appending each element except the last, the
string ", " is appended. Finally a right bracket is appended.
A string is obtained from the string buffer, and returned.
Inherited Methods
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Methods inherited from class java.util.
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Methods inherited from class java.util.
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AbstractCollectioncontainsAll, remove, removeAll,
retainAll, toString
Methods inherited from class java.lang.
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AbstractListequals, hashCode, iterator, listIterator,
listIterator, subList
Objectfinalize, getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface java.util.
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ListcontainsAll, equals, hashCode, iterator, listIterator,
listIterator, remove, removeAll, retainAll, subList