@GwtCompatible(emulated=true) public final class Doubles extends Object
double primitives, that are not already found in either
Double or
Arrays.
See the Guava User Guide article on primitive utilities.
| Modifier and Type | Field and Description |
|---|---|
static int |
BYTES
The number of bytes required to represent a primitive
double value.
|
| Modifier and Type | Method and Description |
|---|---|
static List |
asList(double... backingArray)
Returns a fixed-size list backed by the specified array, similar to
Arrays.
|
static int |
compare(double a, double b)
Compares the two specified
double values.
|
static double[] |
concat(double[]... arrays)
Returns the values from each provided array combined into a single array.
|
static boolean |
contains(double[] array, double target)
Returns
true if
target is present as an element anywhere in
array.
|
static double[] |
ensureCapacity(double[] 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(double value)
Returns a hash code for
value; equal to the result of invoking
((Double) value).hashCode().
|
static int |
indexOf(double[] array, double target)
Returns the index of the first appearance of the value
target in
array.
|
static int |
indexOf(double[] array, double[] 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(double value)
Returns
true if
value represents a real number.
|
static String |
join(String
Returns a string containing the supplied
double values, converted to strings as specified by
Double, and separated by
separator.
|
static int |
lastIndexOf(double[] array, double target)
Returns the index of the last appearance of the value
target in
array.
|
static Comparator |
lexicographicalComparator()
Returns a comparator that compares two
double arrays lexicographically.
|
static double |
max(double... array)
Returns the greatest value present in
array, using the same rules of comparison as
Math.
|
static double |
min(double... array)
Returns the least value present in
array, using the same rules of comparison as
Math.
|
static Converter |
stringConverter()
Returns a serializable converter object that converts between strings and doubles using
Double and
Double.
|
static double[] |
toArray(Collection
Returns an array containing each value of
collection, converted to a
double value in the manner of
Number.
|
static Double |
tryParse(String
Parses the specified string as a double-precision floating point value.
|
public static final int BYTES
double value.
public static int hashCode(double value)
value; equal to the result of invoking
((Double) value).hashCode().
value - a primitive
double value
public static int compare(double a,
double b)
double values. The sign of the value returned is the same as that of
((Double) a).compareTo(b). As with that method,
NaN is treated as greater than all other values, and
0.0 > -0.0.
Note: this method simply delegates to the JDK method Double. It is provided for consistency with the other primitive types, whose compare methods were not added to the JDK until JDK 7.
a - the first
double to compare
b - the second
double to compare
a is less than
b; a positive value if
a is greater than
b; or zero if they are equal
public static boolean isFinite(double value)
true if
value represents a real number. This is equivalent to, but not necessarily implemented as,
!(Double.isInfinite(value) || Double.isNaN(value)).
public static boolean contains(double[] array,
double target)
true if
target is present as an element anywhere in
array. Note that this always returns
false when
target is
NaN.
array - an array of
double values, possibly empty
target - a primitive
double value
true if
array[i] == target for some value of
i
public static int indexOf(double[] array,
double target)
target in
array. Note that this always returns
-1 when
target is
NaN.
array - an array of
double values, possibly empty
target - a primitive
double value
i for which
array[i] == target, or
-1 if no such index exists.
public static int indexOf(double[] array,
double[] target)
target within
array, or
-1 if there is no such occurrence.
More formally, returns the lowest index i such that java.util.Arrays.copyOfRange(array, i, i + target.length) contains exactly the same elements as target.
Note that this always returns -1 when target contains NaN.
array - the array to search for the sequence
target
target - the array to search for as a sub-sequence of
array
public static int lastIndexOf(double[] array,
double target)
target in
array. Note that this always returns
-1 when
target is
NaN.
array - an array of
double values, possibly empty
target - a primitive
double value
i for which
array[i] == target, or
-1 if no such index exists.
public static double min(double... array)
array, using the same rules of comparison as
Math.min(double, double) .
array - a
nonempty array of
double values
array that is less than or equal to every other value in the array
IllegalArgumentException - if
array is empty
public static double max(double... array)
array, using the same rules of comparison as
Math.max(double, double) .
array - a
nonempty array of
double values
array that is greater than or equal to every other value in the array
IllegalArgumentException - if
array is empty
public static double[] concat(double[]... arrays)
concat(new double[] {a, b}, new double[] {}, new double[] {c} returns the array
{a, b, c}.
arrays - zero or more
double arrays
@Beta public static Converter<String ,Double > stringConverter()
Double.valueOf(java.lang.String) and
Double.toString() .
public static double[] ensureCapacity(double[] array,
int minLength,
int padding)
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.
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
array, with guaranteed minimum length
minLength
IllegalArgumentException - if
minLength or
padding is negative
public static Stringjoin(String separator, double... array)
double values, converted to strings as specified by
Double.toString(double) , and separated by
separator. For example,
join("-", 1.0, 2.0, 3.0) returns the string
"1.0-2.0-3.0".
Note that Double formats double differently in GWT sometimes. In the previous example, it returns the string "1-2-3".
separator - the text that should appear between consecutive values in the resulting string (but not at the start or end)
array - an array of
double values, possibly empty
public static Comparator<double[]> lexicographicalComparator()
double arrays lexicographically. That is, it compares, using
compare(double, double)), 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,
[] < [1.0] < [1.0, 2.0] < [2.0].
The returned comparator is inconsistent with Object (since arrays support only identity equality), but it is consistent with Arrays.
public static double[] toArray(Collection<? extends Number > collection)
collection, converted to a
double value in the manner of
Number.doubleValue() .
Elements are copied from the argument collection as if by collection.toArray(). Calling this method is as thread-safe as calling that method.
collection - a collection of
Number instances
collection, in the same order, converted to primitives
NullPointerException - if
collection or any of its elements is null
Collection<Double> before 12.0)
public static List<Double > asList(double... backingArray)
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 Double 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.
backingArray - the array to back the list
@GwtIncompatible(value="regular expressions") @Beta public static DoubletryParse(String string)
'-' (
'\u002D') is recognized as the minus sign.
Unlike Double, this method returns null instead of throwing an exception if parsing fails. Valid inputs are exactly those accepted by Double, except that leading and trailing whitespace is not permitted.
This implementation is likely to be faster than Double.parseDouble if many failures are expected.
string - the string representation of a
double value
string, or
null if
string has a length of zero or cannot be parsed as a
double value