Test if a vector contains a given element

Both the match() (returns the first appearance) and %in% (returns a Boolean) functions are designed for this.

v <- c('a','b','c','e')

'b' %in% v
## returns TRUE

match('b',v)
## returns the first location of 'b', in this case: 2

You can use the %in% operator:

vec <- c(1, 2, 3, 4, 5)
1 %in% vec # true
10 %in% vec # false

Another option to check if a element exists in a vector is by using the %in{}% syntax from the inops package like this:

library(inops)
#> 
#> Attaching package: 'inops'
#> The following object is masked from 'package:base':
#> 
#>     <<-
v <- c('a','b','c','e')
v %in{}% c("b")
#> [1] FALSE  TRUE FALSE FALSE

^{Created on 2022-07-16 by the reprex package (v2.0.1)}