Select groups with more than one distinct value

by

Several possibilities, here’s my favorite

library(data.table)
setDT(df)[, if(+var(number)) .SD, by = from]
#    from number
# 1:    2      1
# 2:    2      2

Basically, per each group we are checking if there is any variance, if TRUE, then return the group values

With base R, I would go with

df[as.logical(with(df, ave(number, from, FUN = var))), ]
#   from number
# 3    2      1
# 4    2      2

Edit: for a non numerical data you could try the new uniqueN function for the devel version of data.table (or use length(unique(number)) > 1 instead

setDT(df)[, if(uniqueN(number) > 1) .SD, by = from]

More Related Contents:

  1. R subset based on range of dates [closed]
  2. Select rows from a data frame based on values in a vector
  3. How to subset matrix to one column, maintain matrix data type, maintain row/column names?
  4. Opposite of %in%: exclude rows with values specified in a vector
  5. How to drop columns by name in a data frame
  6. Subset / filter rows in a data frame based on a condition in a column
  7. How to replace NA with mean by group / subset?
  8. How do I extract a single column from a data.frame as a data.frame?
  9. Subset dataframe by multiple logical conditions of rows to remove
  10. Subset data frame based on multiple conditions [duplicate]
  11. Subsetting R data frame results in mysterious NA rows
  12. Reading multiple files and calculating mean based on user input
  13. Remove groups with less than three unique observations
  14. Collapse rows with overlapping ranges
  15. dplyr – filter by group size
  16. How to subset data in R without losing NA rows?
  17. Using grep to help subset a data frame
  18. Subset based on variable column name
  19. from data table, randomly select one row per group
  20. Return data subset time frames within another timeframes?
  21. Subsetting a dataframe for a specified month and year
  22. Looping through t.tests for data frame subsets in r
  23. Delete duplicate rows in two columns simultaneously [duplicate]
  24. Filter data frame rows based on values in vector
  25. R: How to filter/subset a sequence of dates
  26. Undefined columns selected when subsetting data frame
  27. How to remove rows of a matrix by row name, rather than numerical index?
  28. How to pass “nothing” as an argument to `[` for subsetting?
  29. How to get all possible subsets of a character vector in R?
  30. Filtering rows in R unexpectedly removes NAs when using subset or dplyr::filter

Leave a Comment