Package io.bhagat.util

Class ArrayUtil

java.lang.Object

io.bhagat.util.ArrayUtil

public final class ArrayUtil
extends java.lang.Object

A few of Utility methods for Arrays and ArrayLists

Author:

Bhagat

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ArrayUtil.InvalidSizeException	An exception for when the array or list has the wrong size

Constructor Summary

Constructors

Constructor	Description
ArrayUtil()

Method Summary

Modifier and Type	Method	Description
static <E> E[]	combine(E[] a, E[] b, E[] writeTo)	combine two arrays into a third array
static <E> E[]	copy(E[] arr, E[] arr2)	Copies one array into another
static <E> java.util.ArrayList<E>	copy(java.util.ArrayList<E> list)	Copies the list into a new ArrayList at a different memory location
static <E> int	indexOf(E[] arr, E obj)	finds the index of a certain object in an array
static <E> E[]	map(E[] arr, Function<E,E> function)	maps a function to each element in an array
static <E,T> T[]	map(E[] arr, Function<E,T> function, T[] writeTo)	Maps an array of type E to an array of type T using a function
static <E> E[]	newArrayFromArrayList(java.util.ArrayList<E> list, E[] arr)	This method creates an array from an ArrayList
static java.util.ArrayList<java.lang.Boolean>	newArrayList(boolean... items)	This method creates a new ArrayList with the elements specified by the parameters passed into the method
static java.util.ArrayList<java.lang.Byte>	newArrayList(byte... items)	This method creates a new ArrayList with the elements specified by the parameters passed into the method
static java.util.ArrayList<java.lang.Character>	newArrayList(char... items)	This method creates a new ArrayList with the elements specified by the parameters passed into the method
static java.util.ArrayList<java.lang.Double>	newArrayList(double... items)	This method creates a new ArrayList with the elements specified by the parameters passed into the method
static java.util.ArrayList<java.lang.Float>	newArrayList(float... items)	This method creates a new ArrayList with the elements specified by the parameters passed into the method
static java.util.ArrayList<java.lang.Integer>	newArrayList(int... items)	This method creates a new ArrayList with the elements specified by the parameters passed into the method
static java.util.ArrayList<java.lang.Long>	newArrayList(long... items)	This method creates a new ArrayList with the elements specified by the parameters passed into the method
static java.util.ArrayList<java.lang.Short>	newArrayList(short... items)	This method creates a new ArrayList with the elements specified by the parameters passed into the method
static <E> java.util.ArrayList<E>	newArrayList(E... items)	This method creates a new ArrayList with the elements specified by the parameters passed into the method
static void	printArr(boolean... arr)	Prints out the boolean array in an ArrayList format
static void	printArr(byte... arr)	Prints out the byte array in an ArrayList format
static void	printArr(char... arr)	Prints out the char array in an ArrayList format
static void	printArr(double... arr)	Prints out the double array in an ArrayList format
static void	printArr(float... arr)	Prints out the float array in an ArrayList format
static void	printArr(int... arr)	Prints out the int array in an ArrayList format
static void	printArr(long... arr)	Prints out the long array in an ArrayList format
static void	printArr(short... arr)	Prints out the short array in an ArrayList format
static <E> void	printArr(E... arr)	Prints out an array in an ArrayList format
static double[]	range(double stop)	creates an double array that ranges from 0 to the specified end
static double[]	range(double start, double stop)	creates an double array that ranges from a specified start to the specified end
static double[]	range(double start, double stop, double step)	creates an double array that ranges from a specified to the specified end with a specified step
static float[]	range(float stop)	creates an double array that ranges from 0 to the specified end
static float[]	range(float start, float stop)	creates an double array that ranges from a specified start to the specified end
static float[]	range(float start, float stop, float step)	creates an double array that ranges from a specified to the specified end with a specified step
static <E> E[]	reshape(E[][] arr, E[] arr2)	Reshapes a two dimensional array into a one dimensional array
static <E> E[][]	reshape(E[] arr, E[][] arr2)	Reshapes a one dimensional array into a two dimensional array

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ArrayUtil

public ArrayUtil()

Method Detail

copy

public static <E> java.util.ArrayList<E> copy(java.util.ArrayList<E> list)

Copies the list into a new ArrayList at a different memory location

Type Parameters:

E - the array type

Parameters:

list - the list to be copied

Returns:

the copied list

copy

public static <E> E[] copy(E[] arr,
                           E[] arr2)

Copies one array into another

Type Parameters:

E - the array type

Parameters:

arr - the array to be copied

arr2 - the array to copy to

Returns:

the copied array

reshape

public static <E> E[][] reshape(E[] arr,
                                E[][] arr2)
                         throws ArrayUtil.InvalidSizeException

Reshapes a one dimensional array into a two dimensional array

Type Parameters:

E - the array type

Parameters:

arr - the 1D array

arr2 - the 2D array

Returns:

the 2D array

Throws:

ArrayUtil.InvalidSizeException - thrown when the total number of elements are not the same in each array

reshape

public static <E> E[] reshape(E[][] arr,
                              E[] arr2)
                       throws ArrayUtil.InvalidSizeException

Reshapes a two dimensional array into a one dimensional array

Type Parameters:

E - the array type

Parameters:

arr - the 2D array

arr2 - the 1D array

Returns:

the 1D array

Throws:

ArrayUtil.InvalidSizeException - thrown when the total number of elements are not the same in each array

map

public static <E> E[] map(E[] arr,
                          Function<E,E> function)

maps a function to each element in an array

Type Parameters:

E - the array type

Parameters:

arr - the array

function - the function

Returns:

the array after the mapping

map

public static <E,T> T[] map(E[] arr,
                                  Function<E,T> function,
                                  T[] writeTo)

Maps an array of type E to an array of type T using a function

Type Parameters:

E - the original array type

T - the final array type

Parameters:

arr - the original array

function - the function

writeTo - the array to write to

Returns:

the array written to

indexOf

public static <E> int indexOf(E[] arr,
                              E obj)

finds the index of a certain object in an array

Type Parameters:

E - the array type

Parameters:

arr - the array

obj - the object to look for

Returns:

the index

newArrayFromArrayList

public static <E> E[] newArrayFromArrayList(java.util.ArrayList<E> list,
                                            E[] arr)

This method creates an array from an ArrayList

Type Parameters:

E - the array type

Parameters:

list - the array list to create the array from

arr - the array to write to

Returns:

the new array created

newArrayList

@SafeVarargs
public static <E> java.util.ArrayList<E> newArrayList(E... items)

This method creates a new ArrayList with the elements specified by the parameters passed into the method

Type Parameters:

E - the array type

Parameters:

items - The elements that will fill the ArrayList to be returned

Returns:

A new ArrayList with the items specified from parameters

newArrayList

@SafeVarargs
public static java.util.ArrayList<java.lang.Boolean> newArrayList(boolean... items)

This method creates a new ArrayList with the elements specified by the parameters passed into the method

Parameters:

items - The boolean elements that will fill the ArrayList to be returned

Returns:

A new ArrayList with the items specified from parameters

newArrayList

@SafeVarargs
public static java.util.ArrayList<java.lang.Byte> newArrayList(byte... items)

This method creates a new ArrayList with the elements specified by the parameters passed into the method

Parameters:

items - The byte elements that will fill the ArrayList to be returned

Returns:

A new ArrayList with the items specified from parameters

newArrayList

@SafeVarargs
public static java.util.ArrayList<java.lang.Character> newArrayList(char... items)

This method creates a new ArrayList with the elements specified by the parameters passed into the method

Parameters:

items - The char elements that will fill the ArrayList to be returned

Returns:

A new ArrayList with the items specified from parameters

newArrayList

@SafeVarargs
public static java.util.ArrayList<java.lang.Short> newArrayList(short... items)

This method creates a new ArrayList with the elements specified by the parameters passed into the method

Parameters:

items - The short elements that will fill the ArrayList to be returned

Returns:

A new ArrayList with the items specified from parameters

newArrayList

@SafeVarargs
public static java.util.ArrayList<java.lang.Integer> newArrayList(int... items)

This method creates a new ArrayList with the elements specified by the parameters passed into the method

Parameters:

items - The int elements that will fill the ArrayList to be returned

Returns:

A new ArrayList with the items specified from parameters

newArrayList

@SafeVarargs
public static java.util.ArrayList<java.lang.Long> newArrayList(long... items)

This method creates a new ArrayList with the elements specified by the parameters passed into the method

Parameters:

items - The long elements that will fill the ArrayList to be returned

Returns:

A new ArrayList with the items specified from parameters

newArrayList

@SafeVarargs
public static java.util.ArrayList<java.lang.Float> newArrayList(float... items)

This method creates a new ArrayList with the elements specified by the parameters passed into the method

Parameters:

items - The float elements that will fill the ArrayList to be returned

Returns:

A new ArrayList with the items specified from parameters

newArrayList

@SafeVarargs
public static java.util.ArrayList<java.lang.Double> newArrayList(double... items)

This method creates a new ArrayList with the elements specified by the parameters passed into the method

Parameters:

items - The double elements that will fill the ArrayList to be returned

Returns:

A new ArrayList with the items specified from parameters

printArr

@SafeVarargs
public static <E> void printArr(E... arr)

Prints out an array in an ArrayList format

Type Parameters:

E - the array type

Parameters:

arr - Array to be printed

printArr

@SafeVarargs
public static void printArr(boolean... arr)

Prints out the boolean array in an ArrayList format

Parameters:

arr - Array to be printed

printArr

@SafeVarargs
public static void printArr(byte... arr)

Prints out the byte array in an ArrayList format

Parameters:

arr - Array to be printed

printArr

@SafeVarargs
public static void printArr(char... arr)

Prints out the char array in an ArrayList format

Parameters:

arr - Array to be printed

printArr

@SafeVarargs
public static void printArr(short... arr)

Prints out the short array in an ArrayList format

Parameters:

arr - Array to be printed

printArr

@SafeVarargs
public static void printArr(int... arr)

Prints out the int array in an ArrayList format

Parameters:

arr - Array to be printed

printArr

@SafeVarargs
public static void printArr(long... arr)

Prints out the long array in an ArrayList format

Parameters:

arr - Array to be printed

printArr

@SafeVarargs
public static void printArr(float... arr)

Prints out the float array in an ArrayList format

Parameters:

arr - Array to be printed

printArr

@SafeVarargs
public static void printArr(double... arr)

Prints out the double array in an ArrayList format

Parameters:

arr - Array to be printed

combine

public static <E> E[] combine(E[] a,
                              E[] b,
                              E[] writeTo)

combine two arrays into a third array

Type Parameters:

E - the type of the array

Parameters:

a - the first array to combine

b - the second array to combine

writeTo - the array to combine the other two onto

Returns:

the combined array

range

public static double[] range(double stop)

creates an double array that ranges from 0 to the specified end

Parameters:

stop - where to stop (exclusive)

Returns:

the array

range

public static double[] range(double start,
                             double stop)

creates an double array that ranges from a specified start to the specified end

Parameters:

start - where to start(inclusive)

stop - where to stop (exclusive)

Returns:

the array

range

public static double[] range(double start,
                             double stop,
                             double step)

creates an double array that ranges from a specified to the specified end with a specified step

Parameters:

start - where to start (inclusive)

stop - where to stop (exclusive)

step - the steps to take

Returns:

the array

range

public static float[] range(float stop)

creates an double array that ranges from 0 to the specified end

Parameters:

stop - where to stop (exclusive)

Returns:

the array

range

public static float[] range(float start,
                            float stop)

creates an double array that ranges from a specified start to the specified end

Parameters:

start - where to start(inclusive)

stop - where to stop (exclusive)

Returns:

the array

range

public static float[] range(float start,
                            float stop,
                            float step)

creates an double array that ranges from a specified to the specified end with a specified step

Parameters:

start - where to start (inclusive)

stop - where to stop (exclusive)

step - the steps to take

Returns:

the array