Data Table – Select Value of Column by Name From Another Column

by

More Related Contents:

  1. Subset rows corresponding to max value by group using data.table
  2. Apply a function to every specified column in a data.table and update by reference
  3. dcast warning: ‘Aggregation function missing: defaulting to length’
  4. Fastest way to replace NAs in a large data.table
  5. Fastest way to add rows for missing time steps?
  6. Summarizing multiple columns with data.table
  7. Why is rbindlist “better” than rbind?
  8. Apply multiple functions to multiple columns in data.table
  9. Data.table meta-programming
  10. data.table join then add columns to existing data.frame without re-copy
  11. Convert column classes in data.table
  12. Using lists inside data.table columns
  13. Perform a semi-join with data.table
  14. Find the intersection of overlapping ranges in two tables using data.table function foverlaps
  15. Adding new columns to a data.table by-reference within a function not always working
  16. Referring to data.table columns by names saved in variables
  17. Calculate multiple aggregations on several variables using lapply(.SD, …)
  18. Merge rows in a dataframe where the rows are disjoint and contain NAs
  19. Calculate row-wise maximum
  20. Efficient row-wise operations on a data.table
  21. Replace logical values (TRUE / FALSE) with numeric (1 / 0)
  22. Using setDT inside a function
  23. from data table, randomly select one row per group
  24. How to change type of target column when doing := by group in a data.table in R?
  25. Insert a row in a data.table
  26. rolling joins data.table in R
  27. R data.table apply function to rows using columns as arguments
  28. Efficiently merging two data frames on a non-trivial criteria
  29. assigning by reference into loaded package datasets
  30. calculating sum of previous 3 rows in R data.table (by grid-square)

Leave a Comment