Trace: » data-frames

Data frames

Access columns of a data frame using subscripts
Add one row at a time: df <- c(...)
Convert a multi-way array to a data frame
Process all numeric variables, ignore character variables?: sapply()
Merge data frames (and other database operations): merge()
Create new data frame to hold aggregate values for each factor: aggregate()
Selectively aggregate a data frame: aggregate()
Recode one column, output values into another column: transform(), replace()
Select/subset observations out of a dataframe: basic indexing plus match(), %in%, na.omit(), complete.cases()
Selecting observations for models: subset() and subset= argument
Remove rows from dataframe: special subset()
Remove a set of columns from a data frame by name: subset(), %in%, setdiff()
Generate index vectors
Sort a dataframe: dfr[ order(dfr$col), ]
Count and extract unique rows
List in data.frame (as element): I() and nested list ()

Full content (page names)

tips/data-frames.txt · Last modified: 2008/05/19

R Wiki powered by

and optimized for Firefox