gather converts non-gathered factors to integers

[backlin]

When gathering a number of columns in a data frame, the format of ungathered columns should remain unaffected, but it appears that ungathered factor columns are converted to integers with tidyr 0.3.0 (I use vanilla R 3.2.2 under Ubuntu 14.04).

Create example data

> df <- data.frame(Name = gl(2, 2, 8, c("Alice", "Bob")),
                   A = sample(8), B = sample(8), C = sample(8))
> str(df)
'data.frame':   8 obs. of  4 variables:
 $ Name: Factor w/ 2 levels "Alice","Bob": 1 1 2 2 1 1 2 2
 $ A   : int  3 5 4 7 2 6 1 8
 $ B   : int  7 5 6 2 4 3 1 8
 $ C   : int  8 6 3 4 7 5 1 2

Gather and inspect

> df %>% gather(Col, Value, A:C) %>% str
'data.frame':   24 obs. of  3 variables:
 $ Name : int  1 1 2 2 1 1 2 2 1 1 ...
 $ Col  : Factor w/ 3 levels "A","B","C": 1 1 1 1 1 1 1 1 2 2 ...
 $ Value: int  3 5 4 7 2 6 1 8 7 5 ...

[backlin]

I assume this is a bug since gather of tidyr 0.2.0 behaves as one would expect, i.e. it does not convert the column Name to integer.

[iugrina]

I see the same thing (tidyr 0.3.0 + R 3.2.1/3.2.2).

[vnijs]

Same thing happens on Mac (R 3.2.2). Seems I missed this when testing the pre-release version of tidyr

## with tidyr 0.3
tab <- structure(list(variable = structure(1:5, .Label = c("price", "carat", "depth", "table", "x"), class = "factor"), mean = c(3907.186, 
  0.794283333333333, 61.7526666666667, 57.4653333333333, 5.72182333333333
  )), class = c("tbl_df", "tbl", "data.frame"), row.names = c(NA, 
  -5L), .Names = c("variable", "mean"))

tab %>% gather("function", "value", -1)
tab %>% gather("function", "value", -variable)

## with tidyr 0.2
tab %>% gather("function", "value", -1)
Source: local data frame [5 x 3]

  variable function        value
    (fctr)   (fctr)        (dbl)
1    price     mean 3907.1860000
2    carat     mean    0.7942833
3    depth     mean   61.7526667
4    table     mean   57.4653333
5        x     mean    5.7218233

[ghost]

same with the dev version 0.3.0.9000 :(

devtools::install_version("tidyr", version = "0.2.0", repos = "http://cran.us.r-project.org")

works again

[vnijs]

@ckluss Try the last commit for version 0.2.0

devtools::install_github("hadley/tidyr", ref = "2e08772d154babcc97912bcae8b0b64b65b964ab")

[vnijs]

That works. Thanks @hadley

[ghost]

cool, thank you very much for the fast fix @hadley