Build a blocks_to_rowrecs()/rowrecs_to_blocks() control table that specifies a pivot from a data.frame.

Some discussion and examples can be found here: https://winvector.github.io/FluidData/FluidData.html.

build_pivot_control(
  table,
  columnToTakeKeysFrom,
  columnToTakeValuesFrom,
  ...,
  prefix = columnToTakeKeysFrom,
  sep = NULL,
  tmp_name_source = wrapr::mk_tmp_name_source("bpc"),
  temporary = FALSE
)

# S3 method for default
build_pivot_control(
  table,
  columnToTakeKeysFrom,
  columnToTakeValuesFrom,
  ...,
  prefix = columnToTakeKeysFrom,
  sep = NULL,
  tmp_name_source = wrapr::mk_tmp_name_source("bpcd"),
  temporary = TRUE
)

# S3 method for relop
build_pivot_control(
  table,
  columnToTakeKeysFrom,
  columnToTakeValuesFrom,
  ...,
  prefix = columnToTakeKeysFrom,
  sep = NULL,
  tmp_name_source = wrapr::mk_tmp_name_source("bpc"),
  temporary = FALSE
)

Arguments

table	data.frame to scan for new column names (in-memory data.frame).
columnToTakeKeysFrom	character name of column build new column names from.
columnToTakeValuesFrom	character name of column to get values from.
...	not used, force later args to be by name
prefix	column name prefix (only used when sep is not NULL)
sep	separator to build complex column names.
tmp_name_source	a tempNameGenerator from cdata::mk_tmp_name_source()
temporary	logical, if TRUE use temporary tables

Value

control table

See also

blocks_to_rowrecs

Examples

  d <- data.frame(measType = c("wt", "ht"),
                  measValue = c(150, 6),
                  stringsAsFactors = FALSE)
  build_pivot_control(d,
                      'measType', 'measValue',
                      sep = '_')
#>   measType   measValue
#> 1       wt measType_wt
#> 2       ht measType_ht


d <- data.frame(measType = c("wt", "ht"),
                measValue = c(150, 6),
                stringsAsFactors = FALSE)

ops <- rquery::local_td(d) %.>%
  build_pivot_control(.,
                      'measType', 'measValue',
                      sep = '_')
cat(format(ops))
#> mk_td("d", c(
#>   "measType",
#>   "measValue")) %.>%
#>  non_sql_node(., build_pivot_control(., columnToTakeKeysFrom="measType", columnToTakeValuesFrom="measValue"))

if(requireNamespace("rqdatatable", quietly = TRUE)) {
  library("rqdatatable")
  d %.>%
    ops %.>%
    print(.)
}
#>   measType   measValue
#> 1       wt measType_wt
#> 2       ht measType_ht

if(requireNamespace("RSQLite", quietly = TRUE)) {
  db <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")
  DBI::dbWriteTable(db,
                    'd',
                    d,
                    overwrite = TRUE,
                    temporary = TRUE)
  db %.>%
    ops %.>%
    print(.)
  DBI::dbDisconnect(db)
}
#>   measType   measValue
#> 1       ht measType_ht
#> 2       wt measType_wt