CODEWITHSUNDEEP
rcsv
evt
evt

Reputation: 971

Reading csv file, having numbers and strings in one column

I am importing a 3 column CSV file. The final column is a series of entries which are either an integer, or a string in quotation marks.

Here are a series of example entries:

1,4,"m"
1,5,20
1,6,"Canada"
1,7,4
1,8,5

When I import this using read.csv, these are all just turned in to factors.

How can I set it up such that these are read as integers and strings?

Thank you!

Upvotes: 6

Views: 3878

Answers (3)

joran
joran

Reputation: 173577

EDIT Despite the OP's decision to accept this answer, @Andrie's answer is the preferred solution. My answer is meant only to inform about some odd features of data frames.

As others have pointed out, the short answer is that this isn't possible. data.frames are intended to contain columns of a single atomic type. @Andrie's suggestion is a good one, but just for kicks I thought I'd point out a way to shoehorn this type of data into a data.frame.

You can convert the offending column to a list (this code assumes you've set options(stringsAsFactors = FALSE)):

dat <- read.table(textConnection("1,4,'m'
1,5,20
1,6,'Canada'
1,7,4
1,8,5"),header = FALSE,sep = ",")

tmp <- as.list(as.numeric(dat$V3))
tmp[c(1,3)] <- dat$V3[c(1,3)]
dat$V3 <- tmp

str(dat)
'data.frame':   5 obs. of  3 variables:
 $ V1: int  1 1 1 1 1
 $ V2: int  4 5 6 7 8
 $ V3:List of 5
  ..$ : chr "m"
  ..$ : num 20
  ..$ : chr "Canada"
  ..$ : num 4
  ..$ : num 5

Now, there are all sorts of reasons why this is a bad idea. For one, lots of code that you'd expect to play nicely with data.frames will not like this and either fail, or behave very strangely. But I thought I'd point it out as a curiosity.

Upvotes: 6

Tyler Rinker
Tyler Rinker

Reputation: 109874

No. A dataframe is a series of pasted together vectors (a list of vectors or matrices). Because each column is a vector it can not be classified as both integer and factor. It must be one or the other. You could split the vector apart into numeric and factor ( acolumn for each) but I don't believe this is what you want.

Upvotes: 2

Andrie
Andrie

Reputation: 179428

This is not possible, since a given vector can only have a single mode (e.g. character, numeric, or logical).

However, you could split the vector into two separate vectors, one with numeric values and the second with character values:

vec <- c("m", 20, "Canada", 4, 5)

vnum <- as.numeric(vec)
vchar <- ifelse(is.na(vnum), vec, NA)

vnum
[1] NA 20 NA  4  5

vchar
[1] "m"      NA       "Canada" NA       NA

Upvotes: 9

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