Provide for uniform handling of R's different time-based data classes by extending zoo, maximizing native format information preservation and allowing for user level customization and extension, while simplifying cross-class interoperability.
Changed in xts 0.8-1:
o Dependency now on 1.7-0 or better of zoo (R-forge at present) This build now links to C code moved from xts to zoo. At present this is only for zoo_lag (used in lag and lagts)
Changes in xts 0.7-5:
o try.xts and reclass now are more efficient on xts objects, no longer appending a .RECLASS attribute. This penalty (copying) is shifted to classes that are internally converted to xts.
Changes in xts 0.7-4:
o internal attributes of index are now maintaining timezone (tzone), time class (tclass) information.
[.xts method is now using new C code. This may revert
back as character-based objects are not supported. Changed
for future code refactoring into zoo, as well as performance
gains on integer, double and logical values. Also added in
checks for NAs. drop=TRUE now works correctly in all known
o (cbind)merge.xts and rbind.xts now copy index attributes to handle internal changes to index characteristics (in C code)
o indexTZ.Rd updated to provide information regarding internal changes. Also indexTZ<- is now exported to facilitate timezone changing of xts objects.
Changes in xts 0.7-1:
o subsecond ISO8601 subsetting on dates before 1970 (epoch) is disabled. This is due to a bug in the R implementation of POSIX handling of fractional seconds pre-1970. 10 microsecond granularity is still functional for all other times. Thanks to Andreas Noack Jensen for the early bug report.
o new 'tzone' arg in xts constructor and 'tz' in .parseISO8601 allows for future support of non-system TZ dependent indexing
o internal index attribute (numeric) now can have attributes set (tzone is currently the only one used in xts). These should remain during all xts operations. Still experimental.
o naCheck has been exposed at the C level for use in packages "LinkingTo: xts". See ?xtsAPI for more details.
Changes in xts 0.7-0:
o A new NEWS file.
o print.xts now passes ...
o endpoints speedup and bug fix (thanks Ismail Onur Filiz)
o na.omit bug on logical and NaN fixes (thanks Fabrizio Pollastri and Koert Kuipers)
o fromLast=FALSE for na.locf.xts. Matching to zoo. (thanks to Sandor Benczik)
o LGLSXP support in leadingNA (R fun naCheck)
o fixed logical and NA 'j' subsetting. Thanks Koert Kuipers.
o as.xts and as.timeSeries fixes for timeSeries changes
o merge and subset now support dimensionless xts (non-standard). merge segfault fixed when merging all 3 or more zero-width xts objects and only zero-width objects. Thanks to Koert Kuipers for the report.
o added which.i to [.xts to return i values found via ISO8601 subset string
o new lines.xts and plot.xts, similar to methods in zoo
o lastof now has sec to 10 microsecond precision, and subsec arg to append to secs.
o xts() further consistency in NROW/index check
o align.time error checks for positive n= values (thanks Brian Peterson)
o toPeriod updates in C, almost exported. ~600-1200x faster
o new lag_xts in C. Increased speed and index flexibility.
o endpoints 'days' bug fix
o .makeISO8601 function to create ISO8601 compliant string from xts objects