
The ChangeLog for data.table is the SVN commit log itself :
    svn log svn://svn.r-forge.r-project.org/svnroot/datatable

This NEWS file summarises the main changes.




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        **   CHANGES IN DATA.TABLE VERSION 1.4.1   **
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NEW FEATURES

    o   Vignettes tidied up.
    
        
BUG FIXES

    o   Out of order levels in key columns are now sorted by
        setkey. Thanks to Steve Lianoglou for reporting.

        


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        **                                       **
        **   CHANGES IN DATA.TABLE VERSION 1.4   **
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NEW FEATURES

    o   'by' faster. Memory is allocated first for the result, then
    populated directly by the result of j for each group. Can be 10
    or more times faster than tapply() and aggregate(), see
    timings vignette.
    
    o   j should now be a list(), not DT(), of expressions. Use of
    j=DT(...) is caught internally and replaced with j=list(...).
    
    o   'by' may be a list() of expressions, and a single column name
    no longer has to be quoted. A comma separated string is ok too,
    as before. 
    
    o   key() and key<- added. More R-style alternatives to getkey()
    and setkey().
    
    o   haskey() added. Returns TRUE if a table has a key.
    
    o   radix sorting is now column by column where possible, was
    previously all or nothing. Helps with keys of many columns.
    
    o   Added format method.
    
    o   22 tests added to test.data.table(), now 149.
    
    o   Three vignettes added : FAQ, Intro & Timings


DEPRECATED & DEFUNCT

    o   The DT alias is removed. Use 'data.table' instead to create
    objects. See 2nd new feature above.
    
    o   RUnit framework removed.
    test.data.table() is called from examples in .Rd so 'R CMD check'
    will run it. Simpler. An eval(body(test.data.table))
    is also in the .Rd, to catch namespace issues.
    
    o   Dependency on package 'ref' removed.
    
    o   Arguments removed:  simplify, incbycols and byretn.
    Grouping is simpler now, these are superfluous.
    
    
BUG FIXES

    o   Column classes are now retained by subset and grouping.
    
    o   tail no longer fails when a column 'x' exists.

    
KNOWN PROBLEMS

    o   Minor : Join Inherited Scope not working, contrary
        to the documentation.


NOTES

    o   v1.4 was essentially the branch at rev 44, reintegrated
    at rev 78.




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        **                                       **
        **   CHANGES IN DATA.TABLE VERSION 1.3   **
        **                                       **
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NEW FEATURES

    o   Radix sorting added. Speeds up setkey and add-hoc 'by'
    by factor of 10 or more.
    
    o   Merge method added, much faster than base::merge method
    of data.frame.
    
    o   'by' faster. Logic moved from R into C. Memory is
    allocated for the largest group only, then re-used.
    
    o   The Sub Data is accessible as a whole by j using object
    .SD. This should only be used in rare circumstances. See FAQ.
    
    o   Methods added : duplicated, unique, transform, within,
    [<-, t, Math, Ops, is.na, na.omit, summary
    
    o   Column name rules improved e.g. dots now allowed.
    
    o   as.data.frame.data.table rownames improved.
    
    o   29 tests added to test.data.table(), now 127.
        
        
USER-VISIBLE CHANGES

    o   Default of mb changed, now tables(mb=TRUE)


DEPRECATED & DEFUNCT

    o   ... removed in [.data.table.
    j may not be a function, so this is now superfluous.
    
    
BUG FIXES

    o   Incorrect version warning with R 2.10+ fixed.
    
    o   j enclosure raised one level. This fixes some bugs
    where the j expression previously saw internal variable
    names. It also speeds up grouping a little.


NOTES

    o   v1.3 was not released to CRAN. R-Forge repository only.




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        **                                        **
        **   VERSION 1.2 RELEASED CRAN AUG 2008   **
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