This blog is updated daily..
A general description is here.
gzfile() can recognize and decompress files compressed by 'xz'
if suitable OS support is found at configuration. Since
gzfile() is widely used to read files, this means that for
example load() can read files compressed by 'xv' (and it can
save substantial amounts of space on large data files).
New function xzfile() for use with xz-compressed files (if suitable OS support is found at configuration). This can also read files compressed by some versions of 'lzma'.
New function memCompress() memDecopmress() for in-memory compression and decompression.
gzfile() looks at the file header and so can now also openread bzip2-ed files. It is planned in future to extend this to other forms of compression such as lzma and xz and xv-comppressed files (where supported).
detach() now has an argument 'character.only' with the same meaning as infor library() or require().
R CMD INSTALL has a new option --data-compress to control the compression used when lazy-loading data. THe default is 'gzip': 'bzip2' will give ca 15% better compressionOne new option is --data-compress=bzip2 which will give ca 15% better compression at the expense of slower installation times. Where there is suitable OS support --data-compress=xz can be used, often giving substantially better compression on large datasets at the expense of much slower installation times.
cat() on an unopened connection could close it twice, and file() connections segfaulted on some systems..