R does not import values as numbers

Question

Basic data was generated using a SQL query and the intention is to process data in R. However, while importing from a .csv or from .xlsx, R imports numbers as characters in spite of changing the data-type in the built-in import tool. Further, while performing basic arithmetic operations, following errors were encountered: In Ops.factor((data$A), (data$B)) :‘/’ not meaningful for factors

Is there a simple way to solve this?

Data-set was analysed using the str() function, which revealed that R imported the particular columns as factors.
Used package varhandle and function unfactor to unfactorize the data
Used as.numeric for some columns which were read as characters instead of factors
Tried changing data-types in Excel before importing

data$A <- unfactor(data$A)

data$B <- unfactor(data$B)

data$PERCENTAGE <- (data$B)/(data$A)*100

By what means can R import the data as per specified data-types?

Thank you for the help in advance!

Probably you are using `read.csv` without specify `stringsAsFactors=FALSE` — A. Suliman, Feb 07 '19 at 11:18
It will help to provide [some example data](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example). Almost certainly, a column that you thought was numeric contains characters, which has caused conversion to factors because `stringsAsFactors = FALSE` was not specified. — neilfws, Feb 07 '19 at 11:18
I tried with `stringsAsFactors = F` , but got the following error `non-numeric argument to binary operator` — marine8115, Feb 07 '19 at 11:22
Again, will help to see the command used to read in the data. — neilfws, Feb 07 '19 at 11:25
Example data is a bit difficult to provide....I understand it will help, but some confidentiality clauses are restrictive — marine8115, Feb 07 '19 at 11:30
Does the file have a header? If so and you don't include `header = TRUE`, that will introduce characters into the columns on the first row. — neilfws, Feb 07 '19 at 11:36

score 2 · Answer 1 · answered Feb 07 '19 at 12:12

For csv files I would recommend read_csv from Hadley Wickham's excellent Tidyverse package. It has intelligent defaults that cope with most things I throw at it.

For .xlsx, there is read_excel, also from the Tidyverse package (there are other packages available). Or, alternatively just export a .csv from within Excel and use read_csv.

[Note the Tidyverse's will import these files as a "tibble" which is essentially a data frame on steroids without some of the headaches but is easily converted to a data.frame if you prefer.]

R does not import values as numbers

1 Answers1