stretch_df: Reshape a data frame from "long" to "wide" format

In prettyR: Pretty Descriptive Stats

Description

Reshape a data frame by reducing the multiple rows of repeated variables to a single row for each instance (usually a "case" or object) and stretching out the variables that are not repeated within each case.

Usage

 stretch_df(x,idvar,to.stretch,ordervar=NA,include.ordervar=TRUE)

Arguments

x	A data frame.
idvar	A variable that identifies instances (cases or objects).
to.stretch	Which variables are to be stretched out in the single row.
ordervar	Variable that gives the order of the stretched variables.
include.ordervar	Include the ordering variable in the output.

Details

stretch_df takes a data frame in which at least some instances have multiple rows and reshapes it into a "wide" format with one row per instance. The variable passed as idvar distinguishes the instances, and will be the first column in the new data frame. All other variables in the data frame except those named in to.stretch and ordervar will follow idvar. The variables named in to.stretch will follow the variables that are not repeated in the initial data frame, along with the order variable if include.ordervar is TRUE.

Value

The reshaped data frame.

Note

stretch_df mostly does what other reshaping functions can do, but may be more easy to understand. It will stretch multiple variables, something that some reshaping functions will not do.

Author(s)

Jim Lemon

See Also

reshape

Examples

 # create a data frame with two repeated variables
 longdf<-data.frame(ID=c(rep(111,3),rep(222,4),rep(333,6),rep(444,3)),
  name=c(rep("Joe",3),rep("Bob",4),rep("Sue",6),rep("Bea",3)),
  score1=sample(1:10,16,TRUE),score2=sample(0:100,16),
  scoreorder=c(1,2,3,4,3,2,1,4,6,3,5,1,2,1,2,3))
 stretch_df(longdf,"ID",c("score1","score2"),"scoreorder")

Example output

   ID name score1_1 score1_2 score1_3 score1_4 score1_5 score1_6 score2_1
1 111  Joe        7        4        7       NA       NA       NA       42
2 222  Bob        6       10       10        2       NA       NA       36
3 333  Sue        7       10        6        2        5        3       96
4 444  Bea        2        7        6       NA       NA       NA       44
  score2_2 score2_3 score2_4 score2_5 score2_6 scoreorder_1 scoreorder_2
1       38       93       NA       NA       NA            1            2
2       33       62        9       NA       NA            1            2
3       32       21       37       28       22            1            2
4        7       18       NA       NA       NA            1            2
  scoreorder_3 scoreorder_4 scoreorder_5 scoreorder_6
1            3           NA           NA           NA
2            3            4           NA           NA
3            3            4            5            6
4            3           NA           NA           NA

prettyR documentation built on May 2, 2019, 2:16 a.m.