Class Float

public static final float MAX_VALUE

The maximum positive value a double may represent is 3.4028235e+38f.

Field Value:

2.147483648E9f

public static final float MIN_VALUE

The minimum positive value a float may represent is 1.4e-45.

Field Value:

0.0f

public static final float NEGATIVE_INFINITY

The value of a float representation -1.0/0.0, negative infinity.

Field Value:

-2.147483648E9f

public static final float NaN

All IEEE 754 values of NaN have the same value in Java.

Field Value:

0.0f

public static final float POSITIVE_INFINITY

The value of a float representation 1.0/0.0, positive infinity.

Field Value:

2.147483648E9f

public static final int SIZE

The number of bits needed to represent a float.

Field Value:

32

Since:

1.5

public static final Class TYPE

The primitive type float is represented by this Class object.

Since:

1.1

public Float(double value)

Create a Float from the primitive double specified.

Parameters:

value - the double argument

public Float(float value)

Create a Float from the primitive float specified.

Parameters:

value - the float argument

public Float(String s)

Create a Float from the specified String. This method calls Float.parseFloat().

Parameters:

s - the String to convert

Throws:

NumberFormatException - if s cannot be parsed as a float

NullPointerException - if s is null

See Also:

parseFloat(String)

public byte byteValue()

Return the value of this Float as a byte.

Overrides:

byteValue in interface Number

Returns:

the byte value

Since:

1.1

public static int compare(float x,
                          float y)

Behaves like new Float(x).compareTo(new Float(y)); in other words this compares two floats, special casing NaN and zero, without the overhead of objects.

Parameters:

x - the first float to compare

y - the second float to compare

Returns:

the comparison

Since:

1.4

public int compareTo(Float f)

Compare two Floats numerically by comparing their float values. The result is positive if the first is greater, negative if the second is greater, and 0 if the two are equal. However, this special cases NaN and signed zero as follows: NaN is considered greater than all other floats, including POSITIVE_INFINITY, and positive zero is considered greater than negative zero.

Parameters:

f - the Float to compare

Returns:

the comparison

Since:

1.2

public double doubleValue()

Return the value of this Float as a double

Overrides:

doubleValue in interface Number

Returns:

the double value

public boolean equals(Object obj)

Returns true if obj is an instance of Float and represents the same float value. Unlike comparing two floats with ==, this treats two instances of Float.NaN as equal, but treats 0.0 and -0.0 as unequal.

Note that f1.equals(f2) is identical to floatToIntBits(f1.floatValue()) == floatToIntBits(f2.floatValue()).

Overrides:

equals in interface Object

Parameters:

obj - the object to compare

Returns:

whether the objects are semantically equal

public static int floatToIntBits(float value)

Convert the float to the IEEE 754 floating-point "single format" bit layout. Bit 31 (the most significant) is the sign bit, bits 30-23 (masked by 0x7f800000) represent the exponent, and bits 22-0 (masked by 0x007fffff) are the mantissa. This function collapses all versions of NaN to 0x7fc00000. The result of this function can be used as the argument to Float.intBitsToFloat(int) to obtain the original float value.

Parameters:

value - the float to convert

Returns:

the bits of the float

See Also:

intBitsToFloat(int)

public static int floatToRawIntBits(float value)

Convert the float to the IEEE 754 floating-point "single format" bit layout. Bit 31 (the most significant) is the sign bit, bits 30-23 (masked by 0x7f800000) represent the exponent, and bits 22-0 (masked by 0x007fffff) are the mantissa. This function leaves NaN alone, rather than collapsing to a canonical value. The result of this function can be used as the argument to Float.intBitsToFloat(int) to obtain the original float value.

Parameters:

value - the float to convert

Returns:

the bits of the float

See Also:

intBitsToFloat(int)

public float floatValue()

Return the value of this Float.

Overrides:

floatValue in interface Number

Returns:

the float value

public int hashCode()

Return a hashcode representing this Object. Float's hash code is calculated by calling floatToIntBits(floatValue()).

Overrides:

hashCode in interface Object

Returns:

this Object's hash code

See Also:

floatToIntBits(float)

public static float intBitsToFloat(int bits)

Convert the argument in IEEE 754 floating-point "single format" bit layout to the corresponding float. Bit 31 (the most significant) is the sign bit, bits 30-23 (masked by 0x7f800000) represent the exponent, and bits 22-0 (masked by 0x007fffff) are the mantissa. This function leaves NaN alone, so that you can recover the bit pattern with Float.floatToRawIntBits(float).

Parameters:

bits - the bits to convert

Returns:

the float represented by the bits

See Also:

floatToIntBits(float), floatToRawIntBits(float)

public int intValue()

Return the value of this Integer as an int.

Overrides:

intValue in interface Number

Returns:

the int value

public boolean isInfinite()

Return true if the value of this Float is the same as NEGATIVE_INFINITY or POSITIVE_INFINITY, otherwise return false.

Returns:

whether this Float is (-/+) infinity

public static boolean isInfinite(float v)

Return true if the float has a value equal to either NEGATIVE_INFINITY or POSITIVE_INFINITY, otherwise return false.

Parameters:

v - the float to compare

Returns:

whether the argument is (-/+) infinity

public boolean isNaN()

Return true if the value of this Float is the same as NaN, otherwise return false.

Returns:

whether this Float is NaN

public static boolean isNaN(float v)

Return true if the float has the same value as NaN, otherwise return false.

Parameters:

v - the float to compare

Returns:

whether the argument is NaN

public long longValue()

Return the value of this Integer as a long.

Overrides:

longValue in interface Number

Returns:

the long value

public static float parseFloat(String str)

Parse the specified String as a float. The extended BNF grammar is as follows:

 DecodableString:
      ( [ - | + ] NaN )
    | ( [ - | + ] Infinity )
    | ( [ - | + ] FloatingPoint
              [ f | F | d
                | D] )
 FloatingPoint:
      ( { Digit }+ [ . { Digit } ]
              [ Exponent ] )
    | ( . { Digit }+ [ Exponent ] )
 Exponent:
      ( ( e | E )
              [ - | + ] { Digit }+ )
 Digit: '0' through '9'
 

NaN and infinity are special cases, to allow parsing of the output of toString. Otherwise, the result is determined by calculating n * 10^exponent to infinite precision, then rounding to the nearest float. Remember that many numbers cannot be precisely represented in floating point. In case of overflow, infinity is used, and in case of underflow, signed zero is used. Unlike Integer.parseInt, this does not accept Unicode digits outside the ASCII range.

If an unexpected character is found in the String, a NumberFormatException will be thrown. Leading and trailing 'whitespace' is ignored via String.trim(), but spaces internal to the actual number are not allowed.

To parse numbers according to another format, consider using NumberFormat.

Parameters:

str - the String to convert

Returns:

the float value of s

Throws:

NumberFormatException - if s cannot be parsed as a float

NullPointerException - if s is null

Since:

1.2

See Also:

MIN_VALUE, MAX_VALUE, POSITIVE_INFINITY, NEGATIVE_INFINITY

public short shortValue()

Return the value of this Float as a short.

Overrides:

shortValue in interface Number

Returns:

the short value

Since:

1.1

public static String toHexString(float f)

Convert a float value to a hexadecimal string. This converts as follows:

• A NaN value is converted to the string "NaN".
• Positive infinity is converted to the string "Infinity".
• Negative infinity is converted to the string "-Infinity".
• For all other values, the first character of the result is '-' if the value is negative. This is followed by '0x1.' if the value is normal, and '0x0.' if the value is denormal. This is then followed by a (lower-case) hexadecimal representation of the mantissa, with leading zeros as required for denormal values. The next character is a 'p', and this is followed by a decimal representation of the unbiased exponent.

Parameters:

f - the float value

Returns:

the hexadecimal string representation

Since:

1.5

public String toString()

Convert the float value of this Float to a String. This method calls Float.toString(float) to do its dirty work.

Overrides:

toString in interface Object

Returns:

the String representation

See Also:

toString(float)

public static String toString(float f)

Convert the float to a String. Floating-point string representation is fairly complex: here is a rundown of the possible values. "[-]" indicates that a negative sign will be printed if the value (or exponent) is negative. "<number>" means a string of digits ('0' to '9'). "<digit>" means a single digit ('0' to '9').

Value of Float	String Representation
[+-] 0	[-]0.0
Between [+-] 10-3 and 107, exclusive	[-]number.number
Other numeric value	[-]<digit>.<number> E[-]<number>
[+-] infinity	[-]Infinity
NaN	NaN

Yes, negative zero is a possible value. Note that there is always a . and at least one digit printed after it: even if the number is 3, it will be printed as 3.0. After the ".", all digits will be printed except trailing zeros. The result is rounded to the shortest decimal number which will parse back to the same float.

To create other output formats, use NumberFormat.

Parameters:

f - the float to convert

Returns:

the String representing the float

public static Float valueOf(float val)

Returns a Float object wrapping the value. In contrast to the Float constructor, this method may cache some values. It is used by boxing conversion.

Parameters:

val - the value to wrap

Returns:

the Float

Since:

1.5

public static Float valueOf(String s)

Creates a new Float object using the String.

Parameters:

s - the String to convert

Returns:

the new Float

Throws:

NumberFormatException - if s cannot be parsed as a float

NullPointerException - if s is null

See Also:

parseFloat(String)