Class Floats

java.lang.Object
com.google.common.primitives.Floats
@GwtCompatible(emulated=true) public final class Floats extends Object
Static utility methods pertaining to float primitives, that are not already found in either Float or Arrays.

See the Guava User Guide article on primitive utilities.

Since:
1.0
Author:
Kevin Bourrillion

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    BYTES
    The number of bytes required to represent a primitive float value.

  • Method Summary

    Modifier and Type
    Method
    Description
    static List<Float>
    asList(float... backingArray)
    Returns a fixed-size list backed by the specified array, similar to Arrays.asList(Object[]).
    static int
    compare(float a, float b)
    Compares the two specified float values using Float.compare(float, float).
    static float[]
    concat(float[]... arrays)
    Returns the values from each provided array combined into a single array.
    static float
    constrainToRange(float value, float min, float max)
    Returns the value nearest to value which is within the closed range [min..max].
    static boolean
    contains(float[] array, float target)
    Returns true if target is present as an element anywhere in array.
    static float[]
    ensureCapacity(float[] array, int minLength, int padding)
    Returns an array containing the same values as array, but guaranteed to be of a specified minimum length.
    static int
    hashCode(float value)
    Returns a hash code for value; equal to the result of invoking ((Float) value).hashCode().
    static int
    indexOf(float[] array, float target)
    Returns the index of the first appearance of the value target in array.
    static int
    indexOf(float[] array, float[] target)
    Returns the start position of the first occurrence of the specified target within array, or -1 if there is no such occurrence.
    static boolean
    isFinite(float value)
    Returns true if value represents a real number.
    static String
    join(String separator, float... array)
    Returns a string containing the supplied float values, converted to strings as specified by Float.toString(float), and separated by separator.
    static int
    lastIndexOf(float[] array, float target)
    Returns the index of the last appearance of the value target in array.
    static Comparator<float[]>
    lexicographicalComparator()
    Returns a comparator that compares two float arrays lexicographically.
    static float
    max(float... array)
    Returns the greatest value present in array, using the same rules of comparison as Math.max(float, float).
    static float
    min(float... array)
    Returns the least value present in array, using the same rules of comparison as Math.min(float, float).
    static void
    reverse(float[] array)
    Reverses the elements of array.
    static void
    reverse(float[] array, int fromIndex, int toIndex)
    Reverses the elements of array between fromIndex inclusive and toIndex exclusive.
    static void
    rotate(float[] array, int distance)
    Performs a right rotation of array of "distance" places, so that the first element is moved to index "distance", and the element at index i ends up at index (distance + i) mod array.length.
    static void
    rotate(float[] array, int distance, int fromIndex, int toIndex)
    Performs a right rotation of array between fromIndex inclusive and toIndex exclusive.
    static void
    sortDescending(float[] array)
    Sorts the elements of array in descending order.
    static void
    sortDescending(float[] array, int fromIndex, int toIndex)
    Sorts the elements of array between fromIndex inclusive and toIndex exclusive in descending order.
    static Converter<String,Float>
    stringConverter()
    Returns a serializable converter object that converts between strings and floats using Float.valueOf(java.lang.String) and Float.toString().
    static float[]
    toArray(Collection<? extends Number> collection)
    Returns an array containing each value of collection, converted to a float value in the manner of Number.floatValue().
    static @Nullable Float
    tryParse(String string)
    Parses the specified string as a single-precision floating point value.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • BYTES

      public static final int BYTES
      The number of bytes required to represent a primitive float value.

      Java 8+ users: use Float.BYTES instead.

      Since:
      10.0
      See Also:

  • Method Details

    • hashCode

      public static int hashCode(float value)
      Returns a hash code for value; equal to the result of invoking ((Float) value).hashCode().

      Java 8+ users: use Float.hashCode(float) instead.

      Parameters:
      value - a primitive float value
      Returns:
      a hash code for the value

    • compare

      @InlineMe(replacement="Float.compare(a, b)") public static int compare(float a, float b)
      Compares the two specified float values using Float.compare(float, float). You may prefer to invoke that method directly; this method exists only for consistency with the other utilities in this package.

      Note: this method simply delegates to the JDK method Float.compare(float, float). It is provided for consistency with the other primitive types, whose compare methods were not added to the JDK until JDK 7.

      Parameters:
      a - the first float to compare
      b - the second float to compare
      Returns:
      the result of invoking Float.compare(float, float)

    • isFinite

      public static boolean isFinite(float value)
      Returns true if value represents a real number. This is equivalent to, but not necessarily implemented as, !(Float.isInfinite(value) || Float.isNaN(value)).

      Java 8+ users: use Float.isFinite(float) instead.

      Since:
      10.0

    • contains

      public static boolean contains(float[] array, float target)
      Returns true if target is present as an element anywhere in array. Note that this always returns false when target is NaN.
      Parameters:
      array - an array of float values, possibly empty
      target - a primitive float value
      Returns:
      true if array[i] == target for some value of i

    • indexOf

      public static int indexOf(float[] array, float target)
      Returns the index of the first appearance of the value target in array. Note that this always returns -1 when target is NaN.
      Parameters:
      array - an array of float values, possibly empty
      target - a primitive float value
      Returns:
      the least index i for which array[i] == target, or -1 if no such index exists.

    • indexOf

      public static int indexOf(float[] array, float[] target)
      Returns the start position of the first occurrence of the specified target within array, or -1 if there is no such occurrence.

      More formally, returns the lowest index i such that Arrays.copyOfRange(array, i, i + target.length) contains exactly the same elements as target.

      Note that this always returns -1 when target contains NaN.

      Parameters:
      array - the array to search for the sequence target
      target - the array to search for as a sub-sequence of array

    • lastIndexOf

      public static int lastIndexOf(float[] array, float target)
      Returns the index of the last appearance of the value target in array. Note that this always returns -1 when target is NaN.
      Parameters:
      array - an array of float values, possibly empty
      target - a primitive float value
      Returns:
      the greatest index i for which array[i] == target, or -1 if no such index exists.

    • min

      @GwtIncompatible("Available in GWT! Annotation is to avoid conflict with GWT specialization of base class.") public static float min(float... array)
      Returns the least value present in array, using the same rules of comparison as Math.min(float, float).
      Parameters:
      array - a nonempty array of float values
      Returns:
      the value present in array that is less than or equal to every other value in the array
      Throws:
      IllegalArgumentException - if array is empty

    • max

      @GwtIncompatible("Available in GWT! Annotation is to avoid conflict with GWT specialization of base class.") public static float max(float... array)
      Returns the greatest value present in array, using the same rules of comparison as Math.max(float, float).
      Parameters:
      array - a nonempty array of float values
      Returns:
      the value present in array that is greater than or equal to every other value in the array
      Throws:
      IllegalArgumentException - if array is empty

    • constrainToRange

      public static float constrainToRange(float value, float min, float max)
      Returns the value nearest to value which is within the closed range [min..max].

      If value is within the range [min..max], value is returned unchanged. If value is less than min, min is returned, and if value is greater than max, max is returned.

      Java 21+ users: Use Math.clamp instead.

      Parameters:
      value - the float value to constrain
      min - the lower bound (inclusive) of the range to constrain value to
      max - the upper bound (inclusive) of the range to constrain value to
      Throws:
      IllegalArgumentException - if min > max
      Since:
      21.0

    • concat

      public static float[] concat(float[]... arrays)
      Returns the values from each provided array combined into a single array. For example, concat(new float[] {a, b}, new float[] {}, new float[] {c} returns the array {a, b, c}.
      Parameters:
      arrays - zero or more float arrays
      Returns:
      a single array containing all the values from the source arrays, in order
      Throws:
      IllegalArgumentException - if the total number of elements in arrays does not fit in an int

    • stringConverter

      public static Converter<String,Float> stringConverter()
      Returns a serializable converter object that converts between strings and floats using Float.valueOf(java.lang.String) and Float.toString().
      Since:
      16.0

    • ensureCapacity

      public static float[] ensureCapacity(float[] array, int minLength, int padding)
      Returns an array containing the same values as array, but guaranteed to be of a specified minimum length. If array already has a length of at least minLength, it is returned directly. Otherwise, a new array of size minLength + padding is returned, containing the values of array, and zeroes in the remaining places.
      Parameters:
      array - the source array
      minLength - the minimum length the returned array must guarantee
      padding - an extra amount to "grow" the array by if growth is necessary
      Returns:
      an array containing the values of array, with guaranteed minimum length minLength
      Throws:
      IllegalArgumentException - if minLength or padding is negative

    • join

      public static String join(String separator, float... array)
      Returns a string containing the supplied float values, converted to strings as specified by Float.toString(float), and separated by separator. For example, join("-", 1.0f, 2.0f, 3.0f) returns the string "1.0-2.0-3.0".

      Note that Float.toString(float) formats float differently in GWT. In the previous example, it returns the string "1-2-3".

      Parameters:
      separator - the text that should appear between consecutive values in the resulting string (but not at the start or end)
      array - an array of float values, possibly empty

    • lexicographicalComparator

      public static Comparator<float[]> lexicographicalComparator()
      Returns a comparator that compares two float arrays lexicographically. That is, it compares, using compare(float, float)), the first pair of values that follow any common prefix, or when one array is a prefix of the other, treats the shorter array as the lesser. For example, [] < [1.0f] < [1.0f, 2.0f] < [2.0f].

      The returned comparator is inconsistent with Object.equals(Object) (since arrays support only identity equality), but it is consistent with Arrays.equals(float[], float[]).

      Since:
      2.0

    • sortDescending

      public static void sortDescending(float[] array)
      Sorts the elements of array in descending order.

      Note that this method uses the total order imposed by Float.compare(float, float), which treats all NaN values as equal and 0.0 as greater than -0.0.

      Since:
      23.1

    • sortDescending

      public static void sortDescending(float[] array, int fromIndex, int toIndex)
      Sorts the elements of array between fromIndex inclusive and toIndex exclusive in descending order.

      Note that this method uses the total order imposed by Float.compare(float, float), which treats all NaN values as equal and 0.0 as greater than -0.0.

      Since:
      23.1

    • reverse

      public static void reverse(float[] array)
      Reverses the elements of array. This is equivalent to Collections.reverse(Floats.asList(array)), but is likely to be more efficient.
      Since:
      23.1

    • reverse

      public static void reverse(float[] array, int fromIndex, int toIndex)
      Reverses the elements of array between fromIndex inclusive and toIndex exclusive. This is equivalent to Collections.reverse(Floats.asList(array).subList(fromIndex, toIndex)), but is likely to be more efficient.
      Throws:
      IndexOutOfBoundsException - if fromIndex < 0, toIndex > array.length, or toIndex > fromIndex
      Since:
      23.1

    • rotate

      public static void rotate(float[] array, int distance)
      Performs a right rotation of array of "distance" places, so that the first element is moved to index "distance", and the element at index i ends up at index (distance + i) mod array.length. This is equivalent to Collections.rotate(Floats.asList(array), distance), but is considerably faster and avoids allocation and garbage collection.

      The provided "distance" may be negative, which will rotate left.

      Since:
      32.0.0

    • rotate

      public static void rotate(float[] array, int distance, int fromIndex, int toIndex)
      Performs a right rotation of array between fromIndex inclusive and toIndex exclusive. This is equivalent to Collections.rotate(Floats.asList(array).subList(fromIndex, toIndex), distance), but is considerably faster and avoids allocations and garbage collection.

      The provided "distance" may be negative, which will rotate left.

      Throws:
      IndexOutOfBoundsException - if fromIndex < 0, toIndex > array.length, or toIndex > fromIndex
      Since:
      32.0.0

    • toArray

      public static float[] toArray(Collection<? extends Number> collection)
      Returns an array containing each value of collection, converted to a float value in the manner of Number.floatValue().

      Elements are copied from the argument collection as if by collection.toArray(). Calling this method is as thread-safe as calling that method.

      Parameters:
      collection - a collection of Number instances
      Returns:
      an array containing the same values as collection, in the same order, converted to primitives
      Throws:
      NullPointerException - if collection or any of its elements is null
      Since:
      1.0 (parameter was Collection<Float> before 12.0)

    • asList

      public static List<Float> asList(float... backingArray)
      Returns a fixed-size list backed by the specified array, similar to Arrays.asList(Object[]). The list supports List.set(int, Object), but any attempt to set a value to null will result in a NullPointerException.

      The returned list maintains the values, but not the identities, of Float objects written to or read from it. For example, whether list.get(0) == list.get(0) is true for the returned list is unspecified.

      The returned list may have unexpected behavior if it contains NaN, or if NaN is used as a parameter to any of its methods.

      The returned list is serializable.

      Parameters:
      backingArray - the array to back the list
      Returns:
      a list view of the array

    • tryParse

      @GwtIncompatible public static @Nullable Float tryParse(String string)
      Parses the specified string as a single-precision floating point value. The ASCII character '-' ('\u002D') is recognized as the minus sign.

      Unlike Float.parseFloat(String), this method returns null instead of throwing an exception if parsing fails. Valid inputs are exactly those accepted by Float.valueOf(String), except that leading and trailing whitespace is not permitted.

      This implementation is likely to be faster than Float.parseFloat if many failures are expected.

      Parameters:
      string - the string representation of a float value
      Returns:
      the floating point value represented by string, or null if string has a length of zero or cannot be parsed as a float value
      Throws:
      NullPointerException - if string is null
      Since:
      14.0