Unquote the variable name on the right side of mutate function in dplyr

Question

I am trying to make a function for a creating lagged variable using dplyr and function. But, the problem is that I cannot find how to unquote the variable name on the ri

Answer 1

I think you have to convert the RHS string to a quosure, which you can do with sym from the rlang package. So use

mutate(dt, !!varname_t1 := lag(!!rlang::sym(varname_t0)))

Then your function will yield

lag1_mutate(df, a, 1)
# [1] "a0"
# [1] "a1"
# # A tibble: 5 x 2
#      a0    a1
#   <int> <int>
# 1     3    NA
# 2     4     3
# 3     1     4
# 4     5     1
# 5     2     5

(You set no seed, so my tibble values are different from yours.)