setcolorder
(Package: data.table) :
Fast column reordering of a data.table by reference
In data.table parlance, all set* functions change their input by reference. That is, no copy is made at all, other than temporary working memory, which is as large as one column.. The only other data.table operator that modifies input by reference is :=. Check out the See Also section below for other set* function data.table provides.
● Data Source:
CranContrib
● Keywords: data
● Alias: setcolorder
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duplicated returns a logical vector indicating which rows of a data.table (by key columns or when no key all columns) are duplicates of a row with smaller subscripts.
● Data Source:
CranContrib
● Keywords: data
● Alias: anyDuplicated, anyDuplicated.data.table, duplicated, duplicated.data.table, unique, unique.data.table, uniqueN
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rleid
(Package: data.table) :
Generate run-length type group id
A convenience function for generating a run-length type id column to be used in grouping operations. It accepts atomic vectors, lists, data.frames or data.tables as input.
● Data Source:
CranContrib
● Keywords: data
● Alias: rleid, rleidv
●
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Change rounding to 0, 1 or 2 bytes when joining, grouping or ordering numeric (i.e. double, POSIXct) columns.
● Data Source:
CranContrib
● Keywords: data
● Alias: getNumericRounding, setNumericRounding
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shift
(Package: data.table) :
Fast lead/lag for vectors and lists
lead or lag vectors, lists, data.frames or data.tables implemented in C for speed.
● Data Source:
CranContrib
● Keywords: data
● Alias: lag, lead, shift
●
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setattr
(Package: data.table) :
Set attributes of objects by reference
In data.table, all set* functions change their input by reference. That is, no copy is made at all, other than temporary working memory which is as large as one column. The only other data.table operator that modifies input by reference is :=. Check out the See Also section below for other set* function that data.table provides.
● Data Source:
CranContrib
● Keywords: data
● Alias: setattr, setnames
●
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J
(Package: data.table) :
Creates a Join data table
Creates a data.table to be passed in as the i to a [.data.table join.
● Data Source:
CranContrib
● Keywords: data
● Alias: CJ, J, SJ
●
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