how do you separate a tibble based on a condition in R?

Question

Say, I have the following tibble;

df <- tibble(name = c("CTX_M", "CblA_1", "OXA_1", "ampC"),
             rpkm = c(350, 4, 0, 0))

and I want to split the tibble into one where rpkm = 0, and a second where rpkm > 0.

I've tried to create a function to select the rows where rpkm = 0, as follows

zero <- function(data){
  input = data
  if(input[, 2] == 0){
    n = input
    print(n)
  }
}

but I get the following error when I try to run it like this

Zero <- zero(df)

Warning message:
In if (input[, 2] == 0) { :
  the condition has length > 1 and only the first element will be used

As I'm not so good with R, I'm not sure what is going wrong, or how to approach this?

Answer 1

Alternatively, you can use a handy package called 'dplyr' that's part of a family of packages from the tidyverse. They have a lot of handy functions for working with data.

#library of interest
library(dplyr)

##Your data
df <- tibble(name = c("CTX_M", "CblA_1", "OXA_1", "ampC"),
             rpkm = c(350, 4, 0, 0))

##Using the filter function to get all = 0
df_filt1 <- df %>% 
  filter(rpkm == 0)

##see what the filtering looks like
df_filt1

# A tibble: 2 x 2
  name   rpkm
  <chr> <dbl>
1 OXA_1     0
2 ampC      0

##Using the filter function to get all > 0
df_filt2 <- df %>% 
  filter(rpkm > 0)

##see what the filtering looks like
df_filt2

# A tibble: 2 x 2
  name    rpkm
  <chr>  <dbl>
1 CTX_M    350
2 CblA_1     4