How to filter dynamically using %in% operator?

Question

I want to filter iris using the %in% operator based on the values of the vector fl <- c("virginica","setosa").

I other words, something like

tbl_df(iris) %>% 
  filter_('Species %in% c("virginica","setosa")')

but since this code will go in a shiny app and fl will be generated dynamically, I need to pass fl into my previous script rather than manually typing the values.

Possibly answered by http://stackoverflow.com/a/26509961/3358272 — r2evans, Jul 06 '16 at 18:07
Just `iris %>% filter(Species %in% fl)`, no? Unless you're passing the column name as a string, you don't need the SE function (\*whew\*). — alistaire, Jul 06 '16 at 18:12
It says `fl` will be generated dynamically, but not `Species`. — alistaire, Jul 06 '16 at 18:13
My bad, you're right ... guess I should actually read the question :-) — r2evans, Jul 06 '16 at 18:14
@alistaire The table in my original script is remote, and I get and SQL syntax error unless I use `filter_`. — Dambo, Jul 06 '16 at 18:18
You could just paste it in. I'm dubious that NSE doesn't work, but sadly I can't check with your setup. — alistaire, Jul 06 '16 at 18:26

score 0 · Accepted Answer · edited May 23 '17 at 12:33

(Edit: I'm undeleting this based on the comment that, when pulling from SQL, you have to use the filter_ function or it breaks. That's a separate issue and perhaps a bug in your code, but perhaps this work-around let's you get done what you need. @alistaire's comment works better, but if you need to choose a column dynamically like I initially mis-inferred, then you'll need something like this. Lacking that, this is not an answer so much as an expansion.)

As shown here: https://stackoverflow.com/a/26509961/3358272, instead using %in%:

cn <- "Species"
fl <- c("virginica", "setosa")
filt <- lazyeval::interp(~ col %in% fl, col = as.name(cn))
tbl_df(iris) %>% filter_(filt)
# Source: local data frame [100 x 5]
#    Sepal.Length Sepal.Width Petal.Length Petal.Width Species
#           <dbl>       <dbl>        <dbl>       <dbl>  <fctr>
# 1           5.1         3.5          1.4         0.2  setosa
# 2           4.9         3.0          1.4         0.2  setosa
# 3           4.7         3.2          1.3         0.2  setosa
# 4           4.6         3.1          1.5         0.2  setosa
# 5           5.0         3.6          1.4         0.2  setosa
# ..          ...         ...          ...         ...     ...

How to filter dynamically using %in% operator?

1 Answers1