Various R Programming Tools for Data Manipulation

Various R programming tools for data manipulation, including:
   - medical unit conversions ('ConvertMedUnits', 'MedUnits'),
   - combining objects ('bindData', 'cbindX', 'combine', 'interleave'),
   - character vector operations ('centerText', 'startsWith', 'trim'),
   - factor manipulation ('levels', 'reorder.factor', 'mapLevels'),
   - obtaining information about R objects ('object.size', 'elem', 'env',
     'humanReadable', 'is.what', 'll', 'keep', 'ls.funs',
     'Args','nPairs', 'nobs'),
   - manipulating MS-Excel formatted files ('read.xls',
     'installXLSXsupport', 'sheetCount', 'xlsFormats'),
   - generating fixed-width format files ('write.fwf'),
   - extricating components of date & time objects ('getYear', 'getMonth',
     'getDay', 'getHour', 'getMin', 'getSec'),
   - operations on columns of data frames  ('matchcols', 'rename.vars'),
   - matrix operations ('unmatrix', 'upperTriangle', 'lowerTriangle'),
   - operations on vectors ('case', 'unknownToNA', 'duplicated2', 'trimSum'),
   - operations on data frames ('frameApply', 'wideByFactor'),
   - value of last evaluated expression ('ans'), and
   - wrapper for 'sample' that ensures consistent behavior for both
     scalar and vector arguments ('resample').

Gregory R. Warnes, Ben Bolker, Gregor Gorjanc, Gabor
        Grothendieck, Ales Korosec, Thomas Lumley, Don MacQueen, Arni
        Magnusson, Jim Rogers, and others

c(person("Hong", "Ooi", role="cre", email="hongooi@microsoft.com"),
             person("Revolution", "Analytics", role=c("aut", "cph")),
			 person("Steve", "Weston", role="aut"))

Support for iterators, which allow a programmer to traverse
        through all the elements of a vector, list, or other collection
        of data.

Hong Ooi [cre],
  Revolution Analytics [aut, cph],
  Steve Weston [aut]

c(
  person("Yihui", "Xie", role = c("aut", "cre", "cph"), email = "xie@yihui.name", comment = c(ORCID = "0000-0003-0645-5666")),
  person("Wush", "Wu", role = "ctb"),
  person("Daijiang", "Li", role = "ctb"),
  person("Xianying", "Tan", role = "ctb"),
  person("Salim", "Brüggemann", role = "ctb", email = "salim-b@pm.me", comment = c(ORCID = "0000-0002-5329-5987")),
  person()
  )