I\'m new to R and I\'m trying to sum 2 columns of开发者_如何学JAVA a given dataframe, if both the elements to be summed satisfy a given condition. To make things clear, what I want to do is:
I am generating an ftable (by running ftable on the results of a xtabs command) and I am getting the following.
Given a data frame with a column that contains strings. I would like to plot the frequency of strings that bear a certain pattern. For example
Why doesn\'t a model matrix necessarily have the same number of rows as the data frame? mergem = model.matrix(as.formula(paste(response, \'~ .\')), data=mer开发者_如何学运维gef)
The issue of dropping unused factor levels when subsetting has come up before. Common solutions include using character vectors where possible by declaring
I am trying to make yaml format file from R. I know there is a package for such a 开发者_StackOverflow社区job, but its example is so simple and my object is a bit more tricky !!
I have a list like df_all (see below). A = matrix( ce开发者_Python百科iling(10*runif(8)), nrow=4)
I have data in which each participant made 3 judgments on each of 9 objects (27 judgments).The 9 objects varied in a 3x3 design (within subjects) so there are 2 factors.
I have a series of txt files. I have all these filenames in a csv file X in the Column V1 (X$V1), e.g. a.txt, b.txt....
Does anyone know how to remove an entire column from a data.frame in R? For example if I am given this开发者_如何学Python data.frame:
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