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### B.1.4 Conversions

Functions for converting between strings and numeric values.

`toString( fpVal )`
  Turns a numeric value into a string.

  - Parameters:
    - `fpVal` (floating point): floating point numeric value
  - Return value
    - (String): a string representation of `fpVal`
`toString( intVal )`
  Turns an integer numeric value into a string.

  - Parameters:
    - `intVal` (long integer): integer numeric value
  - Return value
    - (String): a string representation of `intVal`
`toString( charVal )`
  Turns a single character value into a string.

  - Parameters:
    - `charVal` (char): character numeric value
  - Return value
    - (String): a string representation of `charVal`
`toString( byteVal )`
  Turns a byte value into a string.

  - Parameters:
    - `byteVal` (byte): byte numeric value
  - Return value
    - (String): a string representation of `byteVal`
`toString( booleanVal )`
  Turns a boolean value into a string.

  - Parameters:
    - `booleanVal` (boolean): boolean value (true or false)
  - Return value
    - (String): a string representation of `booleanVal` ("`true`" or "`false`")
`toString( objVal )`
  Turns any object value into a string. As applied to existing string values this isn't really useful, but it means that you can apply `toString` to any object value without knowing its type and get a useful return from it.

  - Parameters:
    - `objVal` (Object): non-primitive value
  - Return value
    - (String): a string representation of `objVal`
`parseByte( str )`
  Attempts to interpret a string as a byte (8-bit signed integer) value. If the input string can't be interpreted in this way, a blank value will result.

  - Parameters:
    - `str` (String): string containing numeric representation
  - Return value
    - (byte): byte value of `str`
`parseShort( str )`
  Attempts to interpret a string as a short (16-bit signed integer) value. If the input string can't be interpreted in this way, a blank value will result.

  - Parameters:
    - `str` (String): string containing numeric representation
  - Return value
    - (short integer): byte value of `str`
`parseInt( str )`
  Attempts to interpret a string as an int (32-bit signed integer) value. If the input string can't be interpreted in this way, a blank value will result.

  - Parameters:
    - `str` (String): string containing numeric representation
  - Return value
    - (integer): byte value of `str`
`parseLong( str )`
  Attempts to interpret a string as a long (64-bit signed integer) value. If the input string can't be interpreted in this way, a blank value will result.

  - Parameters:
    - `str` (String): string containing numeric representation
  - Return value
    - (long integer): byte value of `str`
`parseFloat( str )`
  Attempts to interpret a string as a float (32-bit floating point) value. If the input string can't be interpreted in this way, a blank value will result.

  - Parameters:
    - `str` (String): string containing numeric representation
  - Return value
    - (floating point): byte value of `str`
`parseDouble( str )`
  Attempts to interpret a string as a double (64-bit signed integer) value. If the input string can't be interpreted in this way, a blank value will result.

  - Parameters:
    - `str` (String): string containing numeric representation
  - Return value
    - (floating point): byte value of `str`
`parseBigInteger( str )`
  Attempts to interpret a string as a "BigInteger" value. This can be used for working with string representations of integers that can't be stored as an unsigned 64-bit value.

  The result is a `BigInteger` object, which can't be used in normal numeric expressions, but has a number of methods defined on it for comparison, arithmetic, bit manipulation etc. See the java.math.BigInteger javadocs for details.

  - Parameters:
    - `str` (String): string containing numeric representation
  - Return value
    - (BigInteger): BigInteger value of `str`
  - Examples:
    - `parseBigInteger("-20000000000000000023").doubleValue() = -2e19`
    - `parseBigInteger("18446744073709551616").testBit(64) = true`
`parseBigDecimal( str )`
  Attempts to interpret a string as a "BigDecimal" value. This can be used for working with string representations of non-integer values that require more precision or range than is possible in a 64-bit IEEE-754 double precision variable.

  The result is a `BigDecimal` object, which can't be used in normal numeric expressions, but has a number of methods defined on it for comparison, arithmetic, bit manipulation etc. See the java.math.BigDecimal javadocs for details.

  - Parameters:
    - `str` (String): string contining numeric representation
  - Return value
    - (BigDecimal): BigDecimal value of `str`
  - Example:
    - `parseBigDecimal("101").compareTo(parseBigDecimal("102")) = -1`
`parseInts( str )`
  Attempts to interpret a string as an array of integer values. An ad-hoc algorithm is used that tries to extract a list of integers from a string; a comma- or space-separated list of integer values will work, and other formats may or may not.

  The details of this function's behaviour may change in future releases.

  - Parameters:
    - `str` (String): string containing a list of integer values
  - Return value
    - (array of integer): array of integer values
  - Examples:
    - `parseInts("9 8 -23") = [9, 8, -23]`
    - `parseInts("tiddly-pom") = []`
`parseDoubles( str )`
  Attempts to interpret a string as an array of floating point values. An ad-hoc algorithm is used that tries to extract a list of numeric values from a string; a comma- or space-separated list of floating point values will work, and other formats may or may not.

  This function can be used as a hacky way to extract the numeric values from an STC-S (for instance ObsCore/EPNcore `s_region`) string.

  The details of this function's behaviour may change in future releases.

  - Parameters:
    - `str` (String): string containing a list of floating point values
  - Return value
    - (array of floating point): array of floating point values
  - Examples:
    - `parseDoubles("1.3, 99e1, NaN, -23") = [1.3, 990.0, NaN, -23.0]`
    - `parseDoubles("Polygon ICRS 0.8 2.1 9.0 2.1 6.2 8.6") = [0.8, 2.1, 9.0, 2.1, 6.2, 8.6]`
    - `parseDoubles("La la la") = []`
`toByte( value )`
  Attempts to convert the numeric argument to a byte (8-bit signed integer) result. If it is out of range, a blank value will result.

  - Parameters:
    - `value` (floating point): numeric value for conversion
  - Return value
    - (byte): `value` converted to type byte
`toShort( value )`
  Attempts to convert the numeric argument to a short (16-bit signed integer) result. If it is out of range, a blank value will result.

  - Parameters:
    - `value` (floating point): numeric value for conversion
  - Return value
    - (short integer): `value` converted to type short
`toInteger( value )`
  Attempts to convert the numeric argument to an int (32-bit signed integer) result. If it is out of range, a blank value will result.

  - Parameters:
    - `value` (floating point): numeric value for conversion
  - Return value
    - (integer): `value` converted to type int
`toLong( value )`
  Attempts to convert the numeric argument to a long (64-bit signed integer) result. If it is out of range, a blank value will result.

  - Parameters:
    - `value` (floating point): numeric value for conversion
  - Return value
    - (long integer): `value` converted to type long
`toFloat( value )`
  Attempts to convert the numeric argument to a float (32-bit floating point) result. If it is out of range, a blank value will result.

  - Parameters:
    - `value` (floating point): numeric value for conversion
  - Return value
    - (floating point): `value` converted to type float
`toDouble( value )`
  Converts the numeric argument to a double (64-bit signed integer) result.

  - Parameters:
    - `value` (floating point): numeric value for conversion
  - Return value
    - (floating point): `value` converted to type double
`toHex( value )`
  Converts the integer argument to hexadecimal form.

  - Parameters:
    - `value` (long integer): integer value
  - Return value
    - (String): hexadecimal representation of `value`
  - Example:
    - `toHex(42) = "2a"`
`fromHex( hexVal )`
  Converts a string representing a hexadecimal number to its integer value.

  - Parameters:
    - `hexVal` (String): hexadecimal representation of value
  - Return value
    - (integer): integer value represented by `hexVal`
  - Example:
    - `fromHex("2a") = 42`

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TOPCAT - Tool for OPerations on Catalogues And Tables
Starlink User Note253
TOPCAT web page: http://www.starlink.ac.uk/topcat/
Author email: m.b.taylor@bristol.ac.uk
Mailing list: topcat-user@jiscmail.ac.uk