CODEWITHSUNDEEP
rfunctiondplyr
Corel
Corel

Reputation: 633

Passing a column name to written function which uses dplyr functions

I have a function that I wrote which is supposed to filter some values and then produce a crosstabulation. It filters the values using the dplyr filter,select commands.

My problem is that when I pass the name of the column ot the function I get an error, and when I pass the name as string with "" around it, it does not filter the observations. Here is the code:

fnDoCrosstab <- function(a) {
  x <- surv_data1 %>% filter(a != "blank") %>% select(a) %>% as.matrix() %>% as.vector()
  y <- surv_data1 %>% filter(a != "blank") %>% select(segment_name) %>% as.matrix() %>% as.vector()
  CrossTable(x,y, format = "SPSS",prop.chisq = F)
}
fnDoCrosstab(b_thisyear)

Upvotes: 1

Views: 1136

Answers (1)

MrFlick
MrFlick

Reputation: 206167

With the latest version of dplyr (0.7), you can do something like this

library(dplyr)

fnDoCrosstab <- function(a) {
  a <- enquo(a)
  x <- mtcars %>% filter((!!a) != 0) %>% select(mpg, !!a) %>% as.vector()
  x
}
fnDoCrosstab(am)
fnDoCrosstab(vs)

You capture the unevaluated field name with enquo() and then you expand that as necessary with !!

Upvotes: 2

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