How to use map from purrr with dplyr::mutate to create multiple new columns based on column pairs

by

Here is one option with purrr. We get the unique prefix of the names of the dataset (‘nm1’), use map (from purrr) to loop through the unique names, select the column that matches the prefix value of ‘nm1’, add the rows using reduce and the bind the columns (bind_cols) with the original dataset 

library(tidyverse)
nm1 <- names(df) %>% 
          substr(1, 1) %>%
          unique 
nm1 %>% 
     map(~ df %>% 
            select(matches(.x)) %>%
            reduce(`+`)) %>%
            set_names(paste0("sum_", nm1)) %>%
     bind_cols(df, .)
#    a1 b1 c1 a2 b2 c2 sum_a sum_b sum_c
#1  1  4 10  9  3 15    10     7    25
#2  2  5 11 10  4 16    12     9    27
#3  3  6 12 11  5 17    14    11    29
#4  4  7 13 12  6 18    16    13    31
#5  5  8 14 13  7 19    18    15    33

More Related Contents:

  1. tidyverse – prefered way to turn a named vector into a data.frame/tibble
  2. loess regression on each group with dplyr::group_by()
  3. Adding column if it does not exist
  4. Gather multiple sets of columns
  5. How to get summary statistics by group
  6. Is there a dplyr equivalent to data.table::rleid?
  7. Replace NA with previous or next value, by group, using dplyr
  8. Filter rows which contain a certain string
  9. Calculate group mean, sum, or other summary stats. and assign column to original data
  10. Rolling mean (moving average) by group/id with dplyr
  11. Programming with dplyr using string as input
  12. Count number of rows by group using dplyr
  13. Pass a vector of variable names to arrange() in dplyr
  14. Efficient way to filter one data frame by ranges in another
  15. R – add column that counts sequentially within groups but repeats for duplicates
  16. Categorize numeric variable with mutate
  17. Means multiple columns by multiple groups [duplicate]
  18. Delete columns/rows with more than x% missing
  19. adding default values to item x group pairs that don’t have a value (df %>% spread %>% gather seems strange)
  20. dplyr mutate rowwise max of range of columns
  21. dplyr: lead() and lag() wrong when used with group_by()
  22. Reorder rows using custom order
  23. Spreading a two column data frame with tidyr
  24. R dplyr rowwise mean or min and other methods?
  25. Replacement for “rename” in dplyr
  26. Harnessing .f list names with purrr::pmap
  27. How to pass column name as argument to function for dplyr verbs?
  28. How to use data.table within functions and loops?
  29. Override column types when importing data using readr::read_csv() when there are many columns
  30. How to use Dplyr’s Summarize and which() to lookup min/max values

Leave a Comment