Menu
I am manipulating a data frame using the reshape package. When using the melt function, it factorizes my value column, which is a problem because a subset of those values are integers that I want to be able to perform operations on.
Does anyone know of a way to coerce a factor into an integer? Using as.character() will convert it to the correct character, but then I cannot immediately perform an operation on it, and as.integer() or as.numeric() will convert it to the number that system is storing that factor as, which is not helpful.
Thank you!
Jeff
293
There are two steps for converting factor to numeric: Step 1: Convert the data vector into a factor. The factor() command is used to create and modify factors in R. Step 2: The factor is converted into a numeric vector using as. numeric().
We must first convert the factor vector to a character vector, then to a numeric vector. This ensures that the numeric vector contains the actual numeric values instead of the factor levels.
To convert a character vector to a numeric vector, use as. numeric(). It is important to do this before using the vector in any statistical functions, since the default behavior in R is to convert character vectors to factors. Be careful that there are no characters included in any strings, since as.
To convert the data type of all columns from integer to factor, we can use lapply function with factor function.
Quoting directly from the help page for factor:
To transform a factor f to its original numeric values, as.numeric(levels(f))[f] is recommended and slightly more efficient than as.numeric(as.character(f)).
143
You can combine the two functions; coerce to characters thence to numerics:
> fac <- factor(c("1","2","1","2")) > as.numeric(as.character(fac)) [1] 1 2 1 2 If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
