Using readr's read_csv with stdin and textConnection

[Bob]

Hi All,

I'm converting my teaching examples over to the readr package's functions. It looks like read_csv can't accept input from either stdin or textConnection. These provide handy ways to put data in the middle of a program so you don't have to worry how students have their paths set. My examples are below. I hope I've made an error or there's a bug in read_csv, but perhaps read_csv just can't work this way as read.csv can. 

Thanks,

Bob

> mystring <- "id,workshop,gender,q1,q2,q3,q4

+ 1,1,f,1,1,5,1

+ 2,2,f,2,1,4,1

+ 3,1,f,2,2,4,3

+ 4,2,NA,3,1,NA,3

+ 5,1,m,4,5,2,4

+ 6,2,m,5,4,5,5

+ 7,1,m,5,3,4,4

+ 8,2,m,4,5,5,5"

> mydata <- read_csv( textConnection("mystring") )

Error: can only read from a binary connection

Same kind of thing using stdin:

> mydata <- read_csv( stdin() )

Error: can only read from a binary connection

> id,workshop,gender,q1,q2,q3,q4

Error: unexpected ',' in "id,"

> 1,1,f,1,1,5,1

Error: unexpected ',' in "1,"

> 2,2,f,2,1,4,1

Error: unexpected ',' in "2,"

> 3,1,f,2,2,4,3

Error: unexpected ',' in "3,"

> 4,2,NA,3,1,NA,3

Error: unexpected ',' in "4,"

> 5,1,m,4,5,2,4

Error: unexpected ',' in "5,"

> 6,2,m,5,4,5,5

Error: unexpected ',' in "6,"

> 7,1,m,5,3,4,4

Error: unexpected ',' in "7,"

> 8,2,m,4,5,5,5

Error: unexpected ',' in "8,"

> 

> # Blank line above ends input.

> sessionInfo()

R version 3.2.0 (2015-04-16)

Platform: x86_64-w64-mingw32/x64 (64-bit)

Running under: Windows 8 x64 (build 9200)

locale:

[1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252   

[3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C                          

[5] LC_TIME=English_United States.1252    

attached base packages:

[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:

[1] readr_0.1.1

loaded via a namespace (and not attached):

[1] tools_3.2.0 Rcpp_0.11.6

[Hadley Wickham]

read_csv("id,workshop,gender,q1,q2,q3,q4
1,1,f,1,1,5,1
2,2,f,2,1,4,1
3,1,f,2,2,4,3
4,2,NA,3,1,NA,3
5,1,m,4,5,2,4
6,2,m,5,4,5,5
7,1,m,5,3,4,4
8,2,m,4,5,5,5")

;)

Hadley

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[Bob]

Even better! Thanks!

[Jeroen Janssens]

How about:

mydata <- read_csv(file("stdin"))

to read from standard input?

- Jeroen


Op vrijdag 12 juni 2015 18:44:53 UTC+2 schreef Bob:

[Paul De Geest]

But what if I need to use readLines to read in my data first?