Playing w/ data mask example from tidy eval cheatsheet

data_mask_tidy_eval.md

Data mask stuff

Adapted from Tidy evaluation with rlang cheat sheet

library(rlang)

Sometimes a variable name has a value in the global environment and is the name of a variable inside of a data frame (try to avoid having this happen, it’s confusing).

# variables in global env
a <- "life"
b <- "line"

stringr::str_c(a, b)
## [1] "lifeline"

# one row data frame
mydat <- tibble::tibble(a = "coast", b = "guard")

mydat
## # A tibble: 1 x 2
##   a     b    
##   <chr> <chr>
## 1 coast guard

# the experssion we'll evaluate, quoted to use later as a quosure
p <- quo(stringr::str_c(.data$a,!!b))

# using `eval_tidy()`
eval_tidy(p, data = mydat)
## [1] "coastline"

# the experssion we'll evaluate, quoted to use later as a quosure
q <- quo(stringr::str_c(!!a, .data$b))

# using `eval_tidy()`
eval_tidy(q, data = mydat)
## [1] "lifeguard"

data_mask_tidy_eval.Rmd

---
title: "Data mask stuff"
output: github_document
---
```{r include=FALSE, message=FALSE, warning=FALSE}
knitr::opts_chunk$set(
  message = FALSE, warning = FALSE, echo = TRUE, fig.retina = 2, collapse = TRUE
)
```

__Adapted from [Tidy evaluation with rlang cheat sheet](https://github.com/rstudio/cheatsheets/raw/master/tidyeval.pdf)__

```{r}
library(rlang)
```


Sometimes a variable name has a value in the global environment _and_ is the name of a variable inside of a data frame (try to avoid having this happen, it's confusing).

```{r}
# variables in global env
a <- "life"
b <- "line"

stringr::str_c(a, b)
```

```{r}
# one row data frame
mydat <- tibble::tibble(a = "coast", b = "guard")

mydat
```

```{r}
# the experssion we'll evaluate, quoted to use later as a quosure
p <- quo(stringr::str_c(.data$a,!!b))

# using `eval_tidy()`
eval_tidy(p, data = mydat)
```

```{r}
# the experssion we'll evaluate, quoted to use later as a quosure
q <- quo(stringr::str_c(!!a, .data$b))

# using `eval_tidy()`
eval_tidy(q, data = mydat)
```