XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition (617 page)
Read XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition Online
Authors: Michael Kay
Examples
| Expression | Result |
| round-half-to-even(1.1742, 2) | 1.17 |
| round-half-to-even(1.175, 2) | 1.18 |
| round-half-to-even(2.5, 0) | 2.0 |
| round-half-to-even(273, -1) | 270 |
| round-half-to-even(-8500, -3) | -8000 |
Usage
Most of us were probably taught at school that when numbers are rounded, 0.5 should be rounded upward. Professional accountants and statisticians, however, often prefer the “half-to-even” rule because it avoids creating bias: it means that on average, the total of a large set of numbers will remain roughly the same when all the numbers are rounded.
This function is useful when you want to display the results of a numerical calculation to a certain number of decimal places. Floating-point arithmetic often produces rounding errors because decimal values cannot be represented exactly in binary; for example, the result of
0.3e0 div 3
is0.09999999999999999rather than0.1. Rounding the result say to six decimal places by writinground-half-to-even(0.3e0div 3,6)corrects this error, and produces the result0.1.
In XSLT, you can also achieve this rounding by using the
format-number()
function, described on page 788.
See Also
ceiling()
on page 723
floor()
on page 779
format-number()
on page 788
round()
on page 870
seconds-from-dateTime, seconds-from-time
The two functions
seconds-from-dateTime()
and
seconds-from-time()
extract the seconds component (including fractional seconds) from an
xs:dateTime
or
xs:time
value.
Signature
| Argument | Type | Meaning |
| input | xs:time? or xs:dateTime? | The value from which the seconds component is to be extracted. The type of the supplied argument must correspond to the type implied by the function name. If an empty sequence is supplied, an empty sequence is returned. |
| Result | xs:decimal? | The seconds component, in the range 0 to 59.999 … |
Effect
The function returns the seconds component of the supplied
xs:time
or
xs:dateTime
. The value is from the time as expressed in its local timezone (not normalized to UTC).
Examples
| Expression | Result |
| seconds-from-time(xs:time(“12:35:03.142”)) | 3.142 |
| seconds-from-dateTime(xs:dateTime(“2008-02-28T13:55:30-01:00”)) | 30 |
See Also
current-date()
,
-dateTime()
,
-time()
on page 738
format-date()
,
-dateTime()
,
-time()
on page 781
hours-from-dateTime()
,
-time()
on page 800
minutes-from-dateTime()
,
-time()
on page 832
timezone-from-dateTime()
,
-time()
on page 893
seconds-from-duration
This function extracts the value of the seconds component (including fractional seconds) from a normalized
xs:duration
value.
Signature
| Argument | Type | Meaning |
| input | xs:duration? | The value whose seconds component is to be extracted. If an empty sequence is supplied, an empty sequence is returned. |
| Result | xs:decimal? | The seconds component, including any fractional seconds . |
Effect
The function returns the seconds component of the supplied
xs:duration
. The duration value is first normalized so that the number of hours is less than 24, the number of minutes is less than 60, and so on. However, months are never converted to days, or vice-versa. The result will be negative if the duration is negative. The result is therefore a decimal number in the range −60.0 to +60.0, exclusive.
