The Java Developers Almanac 1.4


Order this book from Amazon.

   
Home > List of Packages > java.util  [50 examples] > Arrays  [5 examples]

e1072. Filling Elements in an Array

The Arrays class has conveninent methods for filling arrays of all eight primitive types:
    boolean[] booleanArr = new boolean[10];
    boolean booleanFillValue = false;
    Arrays.fill(booleanArr, booleanFillValue);
    
    byte[] byteArr = new byte[10];
    byte byteFillValue = (byte)0xFF;
    Arrays.fill(byteArr, byteFillValue);
    
    char[] charArr = new char[10];
    char charFillValue = 0xFF;
    Arrays.fill(charArr, charFillValue);
    
    short[] shortArr = new short[10];
    short shortFillValue = 0xFF;
    Arrays.fill(shortArr, shortFillValue);
    
    int[] intArr = new int[10];
    int intFillValue = -1;
    Arrays.fill(intArr, intFillValue);
    
    long[] longArr = new long[10];
    long longFillValue = -1;
    Arrays.fill(longArr, longFillValue);
    
    float[] floatArr = new float[10];
    float floatFillValue = -1;
    Arrays.fill(floatArr, floatFillValue);
    
    double[] doubleArr = new double[10];
    double doubleFillValue = -1;
    Arrays.fill(doubleArr, doubleFillValue);
There is also a method for filling object arrays:
    String[] StringArr = new String[1];
    String StringFillValue = "";
    Arrays.fill(StringArr, StringFillValue);
By default, the nine fill methods shown above set all the elements in the array with the fill value. Each fill method has an overloaded version that can restrict the fill to a contiguous range of elements:
    // Fill elements 0, 1, 2, and 3; the end index is exclusive
    int startIndex = 0;
    int endIndex = 4;
    
    Arrays.fill(booleanArr, startIndex, endIndex, booleanFillValue);
    Arrays.fill(byteArr, startIndex, endIndex, byteFillValue);
    Arrays.fill(charArr, startIndex, endIndex, charFillValue);
    Arrays.fill(shortArr, startIndex, endIndex, shortFillValue);
    Arrays.fill(intArr, startIndex, endIndex, intFillValue);
    Arrays.fill(longArr, startIndex, endIndex, longFillValue);
    Arrays.fill(floatArr, startIndex, endIndex, floatFillValue);
    Arrays.fill(doubleArr, startIndex, endIndex, doubleFillValue);
    Arrays.fill(StringArr, startIndex, endIndex, StringFillValue);

 Related Examples
e338. Comparing Arrays
e339. Shuffling the Elements of a List or Array
e340. Converting a Collection to an Array
e341. Converting an Array to a Collection

See also: Bits    Collections    Dates    Hash Tables    Lists    Property Files    Sets    Sorted Collections    Time    Timers   


© 2002 Addison-Wesley.