Hi, and welcome!
A reproducible example, called a reprex FAQ: What's a reproducible example (`reprex`) and how do I do one? is a great way to get more and better answers, generally. Usually the problem is communicating the data. Sometimes the data is too large, but just a sample that triggers the same issue is OK. Sometimes, it is confidential. That's a bit more tricky, but using a built-in dataset, such as mtcars and transforming it into a comparable structure is possible.
The following snippet is good to know
dput(my_data)
It will spit out an R object that can be cut and pasted as a code block and easily used.
Fortunately, the structure is very simple and isn't much trouble to reproduce.
structure(list(id = c("01", "02", "03", "04"), q = c("Do you skate?",
"Do you skate?", "Do you skate?", "Do you skate?"), a = c("No",
"I don't know", NA, "Yes")), class = c("spec_tbl_df", "tbl_df",
"tbl", "data.frame"), row.names = c(NA, -4L), spec = structure(list(
cols = list(id = structure(list(), class = c("collector_character",
"collector")), q = structure(list(), class = c("collector_character",
"collector")), a = structure(list(), class = c("collector_character",
"collector"))), default = structure(list(), class = c("collector_guess",
"collector")), skip = 1), class = "col_spec"))
The next step is to take the data frame dat and create a new column that encodes a into 1/0/NA. (Why dat? Because data is an R function.
For this we'll use the dplyr package, its mutate function and the base ifelse function).
suppressPackageStartupMessages(library(dplyr))
dat <- structure(list(id = c("01", "02", "03", "04"), q = c("Do you skate?",
"Do you skate?", "Do you skate?", "Do you skate?"), a = c("No",
"I don't know", NA, "Yes")), class = c("spec_tbl_df", "tbl_df",
"tbl", "data.frame"), row.names = c(NA, -4L), spec = structure(list(
cols = list(id = structure(list(), class = c("collector_character",
"collector")), q = structure(list(), class = c("collector_character",
"collector")), a = structure(list(), class = c("collector_character",
"collector"))), default = structure(list(), class = c("collector_guess",
"collector")), skip = 1), class = "col_spec"))
dat <- dat %>% mutate(coded = ifelse(a == "No", 0, NA)) %>% mutate(coded = ifelse(a == "Yes", 1, coded))
dat
#> # A tibble: 4 x 4
#> id q a coded
#> <chr> <chr> <chr> <dbl>
#> 1 01 Do you skate? No 0
#> 2 02 Do you skate? I don't know NA
#> 3 03 Do you skate? <NA> NA
#> 4 04 Do you skate? Yes 1
Created on 2020-01-22 by the reprex package (v0.3.0)