Call apply-like function on each row of dataframe with multiple arguments from each row

by

You can apply apply to a subset of the original data.

 dat <- data.frame(x=c(1,2), y=c(3,4), z=c(5,6))
 apply(dat[,c('x','z')], 1, function(x) sum(x) )

or if your function is just sum use the vectorized version:

rowSums(dat[,c('x','z')])
[1] 6 8

If you want to use testFunc

 testFunc <- function(a, b) a + b
 apply(dat[,c('x','z')], 1, function(x) testFunc(x[1],x[2]))

EDIT To access columns by name and not index you can do something like this:

 testFunc <- function(a, b) a + b
 apply(dat[,c('x','z')], 1, function(y) testFunc(y['z'],y['x']))

More Related Contents:

  1. Repeat each row of data.frame the number of times specified in a column
  2. Filter data.frame rows by a logical condition
  3. Split column at delimiter in data frame [duplicate]
  4. Pass a data.frame column name to a function
  5. Select groups based on number of unique / distinct values
  6. Assign multiple columns using := in data.table, by group
  7. How to replace NA values in a table for selected columns
  8. Remove an entire column from a data.frame in R
  9. Selecting multiple odd or even columns/rows for dataframe
  10. Split dataframe into multiple output files
  11. Replacing values from a column using a condition in R
  12. Split data.frame by value
  13. How to use a string variable to select a data frame column using $ notation [duplicate]
  14. Growing a data.frame in a memory-efficient manner
  15. R list of lists to data.frame
  16. Remove columns from dataframe where some of values are NA
  17. Splitting a data.frame by a variable [duplicate]
  18. Check whether values in one data frame column exist in a second data frame
  19. How do you remove columns from a data.frame?
  20. Unlist a data frame by rows, not columns
  21. Deleting columns from a data.frame where NA is more than 15% of the column length [duplicate]
  22. Using lapply to apply a function over list of data frames and saving output to files with different names
  23. Return df with a columns values that occur more than once [duplicate]
  24. Row-wise sum of values grouped by columns with same name
  25. Replicate each row of data.frame and specify the number of replications for each row?
  26. Convert a data frame to a data.table without copy
  27. How can I merge more than 2 dataframes in R by rownames?
  28. Shifting a column down by one
  29. Identifying where value changes in R data.frame column
  30. What is the first column in R’s mtcars dataset?

Leave a Comment