Split up a dataframe by number of rows

by

Make your own grouping variable.

d <- split(my_data_frame,rep(1:400,each=1000))

You should also consider the ddply function from the plyr package, or the group_by() function from dplyr.

edited for brevity, after Hadley’s comments.

If you don’t know how many rows are in the data frame, or if the data frame might be an unequal length of your desired chunk size, you can do

chunk <- 1000
n <- nrow(my_data_frame)
r  <- rep(1:ceiling(n/chunk),each=chunk)[1:n]
d <- split(my_data_frame,r)

You could also use

r <- ggplot2::cut_width(1:n,chunk,boundary=0)

For future readers, methods based on the dplyr and data.table packages will probably be (much) faster for doing group-wise operations on data frames, e.g. something like

(my_data_frame 
   %>% mutate(index=rep(1:ngrps,each=full_number)[seq(.data)])
   %>% group_by(index)
   %>% [mutate, summarise, do()] ...
)

There are also many answers here

More Related Contents:

  1. Split data frame string column into multiple columns
  2. How to split a data frame?
  3. Split a large dataframe into a list of data frames based on common value in column
  4. Calculate the mean of every 13 rows in data frame
  5. Splitting a dataframe string column into multiple different columns [duplicate]
  6. Split dataframe into multiple output files
  7. Split data.frame by value
  8. Splitting a string into new rows in R [duplicate]
  9. Splitting a large data frame into smaller segments
  10. Split Data Frame into Rows of Fixed Size
  11. Split dataframe using two columns of data and apply common transformation on list of resulting dataframes
  12. Split a column by group [duplicate]
  13. Drop unused factor levels in a subsetted data frame
  14. Why is it not advisable to use attach() in R, and what should I use instead?
  15. Subset data frame based on multiple conditions [duplicate]
  16. R – Concatenate two dataframes?
  17. How to convert dataframe into time series?
  18. Merge unequal dataframes and replace missing rows with 0
  19. First entry from string split
  20. Removing display of row names from data frame
  21. Split one row into multiple rows [duplicate]
  22. Shift values in single column of dataframe up
  23. finding close match from data frame 1 in data fame 2
  24. Combine several data frames in the global environment by row (rbind)
  25. use multiple columns as variables with sapply
  26. Reshape a dataframe to long format with multiple sets of measure columns [duplicate]
  27. Count number of non-NA values for every column in a dataframe [duplicate]
  28. Difference between `names(df[1])
  29. How to create a new variable in a data.frame based on a condition?
  30. Interpolating timeseries

Leave a Comment