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rfiltersyntaxdplyrtidyverse
Bill Raynor
Bill Raynor

Reputation: 433

How to use column numbers in the dplyr filter function

How do I use the dplyr::filter() function with column numbers, rather than column names?

As an example, I'd like to pick externally selected columns and return the rows that are all zeros. For example, for a data frame like this

> test
# A tibble: 10 x 4
    C001  C007  C008  C020
   <dbl> <dbl> <dbl> <dbl>
 1    -1    -1     0     0
 2     0     0     0     0
 3     1     1     0     0
 4    -1    -1     0     0
 5     0     0     0    -1
 6     0     0     0     1
 7     0     1     1     0
 8     0     0    -1    -1
 9     1     1     0     0
10     0     0     0     0

and a vector S = c(1,3,4) How would I pick all the rows in test where all(x==0)? I can do this with an test[apply(test[,S] 1, function(x){all(x==0)},] but I'd like to use this as part of a %>% pipeline.

I have not been able to figure out the filter() syntax to use column numbers rather than names. The real data has many more columns (>100) and rows and the column numbers are supplied by an external algorithm.

Upvotes: 5

Views: 2969

Answers (1)

A. Suliman
A. Suliman

Reputation: 13135

Use filter_at with all_vars

library(dplyr)
df %>% filter_at(c(1,3,4), all_vars(.==0))

 C001 C007 C008 C020
1    0    0    0    0
2    0    0    0    0

Upvotes: 4

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