R：字符变量在cbind（）和data.frame（）之后变为数字

Question

I try to combine one column with a data.frame. I used both cbind() and data.frame(), but after that the character variable became a numeric one.

>is.character(new_listing_zip)
[1] TRUE
> new_race_disp_use2 <- cbind(new_listing_zip,opo_trans) 
> is.character(new_race_disp_use2$new_listing_zip)
[1] FALSE

> is.character(new_listing_zip)
[1] TRUE
> new_race_disp_use2 <- data.frame(new_listing_zip,opo_trans) 
> is.character(new_race_disp_use2$new_listing_zip)
[1] FALSE

Does anyone could help me with this? Thank you.

Answer 1

if you check the help files for data.frame() I think you will find your answer

 ?data.frame

You'll want to set your

options(stringsAsFactors = TRUE)

to change it globally or just set your parameter for

stringsAsFactors = TRUE

when declaring your data.frame, assuming these are actual character strings. Otherwise I would simply declare your variable as a factor when joining it

new_race_disp_use2 <- cbind(factor(new_listing_zip),opo_trans)

Now of course if your 'factor' is actually a numeric you want as a string (seemingly zip codes in your example) you'll want to either set your zip codes as strings to begin with using quotes (ie "12345") or set the data type after the data.frame is built

 new_race_disp_use$new_listing_zip <- as.character(new_race_disp$new_listing_zip)

or

as.factor(varName) 

or simply

factor() instead of as.character()