Returning above and below rows of specific rows in r dataframe

by

Try that:

extract.with.context <- function(x, rows, after = 0, before = 0) {

  match.idx  <- which(rownames(x) %in% rows)
  span       <- seq(from = -before, to = after)
  extend.idx <- c(outer(match.idx, span, `+`))
  extend.idx <- Filter(function(i) i > 0 & i <= nrow(x), extend.idx)
  extend.idx <- sort(unique(extend.idx))

  return(x[extend.idx, , drop = FALSE])
}

dat <- data.frame(x = 1:26, row.names = letters)
extract.with.context(dat, c("a", "b", "j", "y"), after = 3, before = 1)
#    x
# a  1
# b  2
# c  3
# d  4
# e  5
# i  9
# j 10
# k 11
# l 12
# m 13
# x 24
# y 25
# z 26

More Related Contents:

  1. Case Statement Equivalent in R
  2. Why does X[Y] join of data.tables not allow a full outer join, or a left join?
  3. Subset data frame based on multiple conditions [duplicate]
  4. UTF-8 file output in R
  5. Using Rcpp within parallel code via snow to make a cluster
  6. Extract every nth element of a vector
  7. How to get a reversed, log10 scale in ggplot2?
  8. Is there a R function that applies a function to each pair of columns?
  9. Changing Fonts for Graphs in R
  10. In R markdown in RStudio, how can I prevent the source code from running off a pdf page?
  11. Collapse rows with overlapping ranges
  12. Create columns from factors and count [duplicate]
  13. Unable to change Python path in reticulate
  14. Joining aggregated values back to the original data frame [duplicate]
  15. geom_boxplot with precomputed values
  16. How to avoid: read.table truncates numeric values beginning with 0
  17. Automatically create formulas for all possible linear models
  18. How to add a index by set of data when using rbindlist?
  19. Split one row into multiple rows [duplicate]
  20. knitr: How to prevent text wrapping in output?
  21. Make readline wait for input in R
  22. Shift values in single column of dataframe up
  23. Find K nearest neighbors, starting from a distance matrix
  24. Changing the order of dodged bars in ggplot2 barplot
  25. How to collapse many records into one while removing NA values
  26. Function to concatenate paths?
  27. How can I label points in this scatterplot?
  28. Error when using predict() on a randomForest object trained with caret’s train() using formula
  29. Convert two-digit years to four-digit years with correct century
  30. Dealing with very small numbers in R

Leave a Comment