Multiple variable filters in r

Question

I\'m trying to figure out the best way how to use multiple variable filters in R.

Usually have up to 100 variables (in one condition) and need to filter cases where ANY

Answer 1

You're looking for a function that works on every row of your dataframe. That's what "apply" is doing. It's equally fast as the solution of others, but easy to handle:

system.time(
((x1==37) | (x2==37) | (x3==37) | (x4==37) | (x5==37) | (x6==37) | (x7==37) | (x8==37) | (x9==37) | (x10==37))
 )
# user  system elapsed 
# 0.02    0.00    0.02 

 system.time(
    apply(df, 1 , function(x) any(x[2:11]==37))
 )
# user  system elapsed 
# 0.59    0.00    0.61 

Although you don't ask for changing data structure, I recommend have a look at tidy data. With a rearranged version of your dataframe you can do filterings efficient and easy to handle:

library(tidyr)
df2 = gather(df, key, value, -id)

system.time(
    select(filter(df, value==37), id)
)
#   user  system elapsed 
#   0.02    0.00    0.02