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Can a factor be numeric?
numeric applied to a factor is meaningless, and may happen by implicit coercion. To transform a factor f to approximately its original numeric values, as. numeric(levels(f))[f] is recommended and slightly more efficient than as.
How do you convert a factor to a numeric?
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.
How do I convert factor to numeric in R?
How to Convert a Factor in R
- Sometimes you need to explicitly convert factors to either text or numbers.
- Use as.character() to convert a factor to a character vector: > as.character(directions.factor) [1] “North” “East” “South” “South”
- Use as.numeric() to convert a factor to a numeric vector.
How do I change a column to numeric in R?
To convert columns of an R data frame from integer to numeric we can use lapply function. For example, if we have a data frame df that contains all integer columns then we can use the code lapply(df,as. numeric) to convert all of the columns data type into numeric data type.
How does as factor work in R?
as. factor does give a quick return, but factor is not a real “no-op”. Let’s profile factor to see what it has done. It first sort the unique values of the input vector f , then converts f to a character vector, finally uses factor to coerces the character vector back to a factor.
Can a factor Vector be converted to a numeric vector?
Take a data vector ‘V’ consisting of directions and its factor will be converted into numeric. If the factor is number, first convert it to a character vector and then to numeric. If a factor is a character then you need not convert it to a character. And if you try converting an alphabet character to numeric it will return NA.
How to convert data frame column from factor to numeric?
But this is really treating the symptom, not curing the cause. A better approach is to use the colClasses argument to read.table and related functions to tell R that the column should be numeric so that it never creates a factor and creates numeric. This will put in NA for any values that do not convert to numeric.
How does the unfactor function convert to a numeric?
The unfactor function converts to character data type first and then converts back to numeric. Type unfactor at the console and you can see it in the middle of the function. Therefore it doesn’t really give a better solution than what the asker already had. – CJB Jan 25 ’16 at 9:32.
How to transform factor f to a numeric value?
To transform a factor f to approximately its original numeric values, as.numeric (levels (f)) [f] is recommended and slightly more efficient than as.numeric (as.character (f)). This is FAQ 7.10. Others have shown how to apply this to a single column in a data frame, or to multiple columns in a data frame.