Extracting emojis for each lesson

lesson_emojis.Rmd

---
title: "Lesson emojis"
author: "Mine Çetinkaya-Rundel"
date: "11/21/2018"
output: 
  html_document: 
    highlight: pygments
    theme: cerulean
---

Start by loading packages.

```{r message=FALSE}
library(fs)
library(tidyverse)
library(emo)
library(here)
library(glue)
library(knitr)
```

Use **fs** to get a list of all `Rmd` files in the subfolders of the
`static/slides` folder.

```{r}
files <- fs::dir_info(here("static", "slides"), recursive = TRUE, glob = "*.Rmd") %>%
  slice(-1) %>%
  mutate(path = as.character(path)) %>%
  select(path)
```

Define two functions for extracting the title and emoji keyword from the second 
line of each Rmd file. This is the line that contains the `title` in the YAML.

```{r}
extract_title <- function(x){
  read_lines(as.character(x), skip = 1, n_max = 1) %>%
    str_extract(" .*\\<") %>%
    str_remove('\"') %>% 
    str_remove("\\<") %>% 
    str_trim()
}
extract_keyword <- function(x){
  read_lines(as.character(x), skip = 1, n_max = 1) %>%
    str_extract("emo::ji\\(.*\\)") %>%
    str_remove("emo::ji\\('") %>% 
    str_remove("'\\)")
}
```

Grab titles, keywords, and find corresponding emojis, with a little bit of 
help from [here](https://github.com/hadley/emo/blob/master/README.Rmd).

```{r results='asis'}
files <- files %>%
  mutate(
    title = map_chr(path, extract_title),
    keyword = map_chr(path, extract_keyword),
    emoji = map_chr(keyword, function(x) glue(emo::ji_name[x], collapse = ""))
  )
```

View titles, keywords, and emojis.

```{r}
files %>%
  select(title, emoji, keyword) %>%
  kable()
```