How to store filter expressions as strings?

Question

For the analysis of a species database, I often need to change lots of criteria, depending on the projects scope etc.

As it is very inconvenient to always change the

Answer 1

In addition to @Konrad's methods, if the expression is a string, then we can use parse_expr from rlang

library(rlang)
library(dplyr)
df1 %>% 
    filter(!! parse_expr(expr1))
#   col_A col_B
#1     A     1

data

 df1 <- data.frame(col_A = LETTERS[1:10],
           col_B = 1:10,
           stringsAsFactors = FALSE)

expr1 <-  "col_A == 'A' & col_B == 1"