Transpose / reshape dataframe without “timevar” from long to wide format

by

With the data.table package, this could easily be solved with the new rowid function:

library(data.table)
dcast(setDT(d1), 
      Name ~ rowid(Name, prefix = "medication"), 
      value.var = "MedName")

which gives:

   Name    medication1     medication2       medication3
1 Name1  atenolol 25mg    aspirin 81mg  sildenafil 100mg
2 Name2  atenolol 50mg  enalapril 20mg              <NA>

Another method (commonly used before version 1.9.7):

dcast(setDT(d1)[, rn := 1:.N, by = Name], 
      Name ~ paste0("medication",rn), 
      value.var = "MedName")

giving the same result.

A similar approach, but now using the dplyr and tidyr packages:

library(dplyr)
library(tidyr)
d1 %>%
  group_by(Name) %>%
  mutate(rn = paste0("medication",row_number())) %>%
  spread(rn, MedName)

which gives:

Source: local data frame [2 x 4]
Groups: Name [2]

    Name   medication1    medication2      medication3
  (fctr)         (chr)          (chr)            (chr)
1  Name1 atenolol 25mg   aspirin 81mg sildenafil 100mg
2  Name2 atenolol 50mg enalapril 20mg               NA

More Related Contents:

  1. How to reshape data from long to wide format
  2. Reshaping data.frame from wide to long format
  3. Reshaping multiple sets of measurement columns (wide format) into single columns (long format)
  4. Reshape multiple value columns to wide format
  5. Grouping functions (tapply, by, aggregate) and the *apply family
  6. The difference between bracket [ ] and double bracket [[ ]] for accessing the elements of a list or dataframe
  7. Numbering rows within groups in a data frame
  8. How can I view the source code for a function?
  9. Calculate the mean by group
  10. Remove rows with all or some NAs (missing values) in data.frame
  11. Side-by-side plots with ggplot2
  12. Find the day of a week
  13. Pasting two vectors with combinations of all vectors’ elements
  14. Rename multiple columns by names
  15. Error in : target of assignment expands to non-language object
  16. Convert integer to class Date
  17. How to unload a package without restarting R
  18. as.Date returning NA while converting from ‘ddmmmyyyy’
  19. How to search for “R” materials? [closed]
  20. What is the difference between = and ==?
  21. Set default CRAN mirror permanent in R
  22. Read SAS sas7bdat data into R
  23. Is there an R function to reshape this data from long to wide?
  24. What is the difference between = and == in R?
  25. Transposing a dataframe maintaining the first column as heading
  26. Should I use a data.frame or a matrix?
  27. Variable name restrictions in R
  28. Different legend-keys inside same legend in ggplot2
  29. Plot two graphs in a same plot
  30. Convert a vector into a list, each element in the vector as an element in the list

Leave a Comment