longer_dt: Pivot data from wide to long

In hope-data-science/tidydt: Tidy Verbs for 'data.table'

Description

Analogous function for pivot_longer in tidyr.

Usage

longer_dt(
  data,
  ...,
  gathered_name = "variable",
  gathered_value = "value",
  group_to_keep = NULL,
  negate = FALSE,
  na.rm = FALSE
)

Arguments

data	A data.frame
...	Pattern for unchanged group or unquoted names. Pattern can accept regular expression to match column names. If set 'negate = TRUE', return non-matching columns.
gathered_name	name for the measured variable names column. The default name is 'variable'.
gathered_value	name for the molten data values column(s). The default name is 'value'.
group_to_keep	Group to keep, namely vector of unchanged variables. Can be integer (corresponding id column numbers) or character (id column names) vector.
negate	If TRUE, return non-matching elements.
na.rm	If TRUE, NA values will be removed from the molten data.

Value

A data.table

See Also

melt

pivot_longer

Examples

## Example 1:
stocks = data.frame(
  time = as.Date('2009-01-01') + 0:9,
  X = rnorm(10, 0, 1),
  Y = rnorm(10, 0, 2),
  Z = rnorm(10, 0, 4)
)

stocks

stocks %>%
  longer_dt(time)

stocks %>%
  longer_dt("ti")

# Example 2:

library(tidyr)
library(tidydt)

billboard %>%
  longer_dt(
    "wk",
    gathered_name = "week",
    gathered_value = "rank",
    na.rm = TRUE,negate = TRUE
  )

# or use:
 billboard %>%
   longer_dt(
     artist,track,date.entered,
     gathered_name = "week",
     gathered_value = "rank",
     na.rm = TRUE,negate = TRUE
   )

 # or use:
 billboard %>%
   longer_dt(
     group_to_keep = 1:3,
     gathered_name = "week",
     gathered_value = "rank",
     na.rm = TRUE,negate = TRUE
   )

hope-data-science/tidydt documentation built on Feb. 21, 2020, 10:25 a.m.