Given two data frames: df1 = data.frame(CustomerId = c(1:6), Product = c(rep("Toaster", 3), rep("Radio", 3))) df2 = data.frame(CustomerId = c(2, 4, 6), State = c(rep("Alabama", 2), rep("Ohio", 1))) ...
How do I make a list of data frames and how do I access each of those data frames from the list? I can't find a simple example of this anywhere. SO is telling me my post is too short, so I'll get th...
I have some trouble to convert my data.frame from a wide table to a long table. At the moment it looks like this: Code Country 1950 1951 1952 1953 1954 AFG Afghanistan 20,249 ...
I want to sort a data.frame by multiple columns. For example, with the data.frame below I would like to sort by column z (descending) then by column b (ascending): dd <- data.frame(b = factor(c("...
I wish to order a data frame based on different columns, one at a turn. I have a character vector with the relevant column names on which the order should be based: parameter <- c("market_value_LO...
I have very large tables (30 million rows) that I would like to load as a dataframes in R. read.table() has a lot of convenient features, but it seems like there is a lot of logic in the implementati...
I have a list of many data.frames that I want to merge. The issue here is that each data.frame differs in terms of the number of rows and columns, but they all share the key variables (which I've call...
From a data frame, is there a easy way to aggregate (i.e. sum) multiple variables simultaneously? Below are some sample data: library(lubridate) days = 365*2 date = seq(as.Date("2000-01-01"), length...
I'd like to take data of the form before = data.frame(attr = c(1,30,4,6), type=c('foo_and_bar','foo_and_bar_2')) attr type 1 1 foo_and_bar 2 30 foo_and_bar_2 3 4 foo_and_bar 4 ...
I have a data.frame that looks like this. x a 1 x b 2 x c 3 y a 3 y b 3 y c 2 I want this in matrix form so I can feed it to heatmap to make a plot. The result should look something like: ...