An explanation: When you melt, you are combining multiple columns into one. In this case, you are combining factor columns, each of which has a levels attribute. These levels are not the same across columns because your factors are actually different. melt just coerces each factor to character and drops their attributes when creating the value column in the result. In … Read more
I think you’re asking how to compute the mean of a variable in a data frame, given the name of the column. There are two typical approaches to doing this, one indexing with [[ and the other indexing with [:
I’ve been trying to run this function and the “non-numeric argument to binary operator” pops up. I’ve seen quite a few questions similar to mine, yet I still can’t figure out what is the issue with my code. The error happens on the sixth line Itl[j] <- (Itl[j] + incrm[j]) %% N. The code for the … Read more
lines() or points() will add to the existing graph, but will not create a new window. So you’d need to do
Is there a way to create a “dictionary” in R, such that it has pairs? Something to the effect of: I’m asking this because I am actually looking for a two categorial variables function. So that if x=dictionary(c(“a”,”b”),c(5,2)) I want to compute x1^2+x2 on all combinations of x keys And then I want to be … Read more
We need to use concatenate to create a vector instead of list and if we are using list, then unlist it to create a vector as data.frame takes a vector of column names (column index) or row names (row index) to subset the columns or rows
I am fairly new to R and I have the following queries : I am trying to generate a plot in R which has multiple lines (data series). Each of these lines is a category and I want it to have a unique color. Currently my code is setup in this way : First, I … Read more
The warning message is because your “Type” variable was made a factor and “lunch” was not a defined level. Use the stringsAsFactors = FALSE flag when making your data frame to force “Type” to be a character.
Here are some ways of computing the residual sum of squares (RSS) using the built-in anscombe data set: Regarding the last one, note that summary(fm)$df[2] and summary(fm)$sigma are shown in the summary(fm) output in case you want to calculate RSS using only a printout from summary. In particular, for the output shown in the question df[2] = 116 and sigma = 1.928 so RSS … Read more
You can just use sum(people$Weight). sum sums up a vector, and people$Weight retrieves the weight column from your data frame. Note – you can get built-in help by using ?sum, ?colSums, etc. (by the way, colSums will give you the sum for each column).