---
title: "IKEA Furniture"
date: 2020-11-03
output: html_output
---

# TidyTuesday

Join the R4DS Online Learning Community in the weekly #TidyTuesday event!
Every week we post a raw dataset, a chart or article related to that dataset, and ask you to explore the data.
While the dataset will be “tamed”, it will not always be tidy! As such you might need to apply various R for Data Science techniques to wrangle the data into a true tidy format.
The goal of TidyTuesday is to apply your R skills, get feedback, explore other’s work, and connect with the greater #RStats community!
As such we encourage everyone of all skills to participate!

```{r setup, include=FALSE}

knitr::opts_chunk$set(echo = TRUE)

library(tidyverse)
library(tidytuesdayR)
library(scales)
theme_set(theme_light())

```

# Load the weekly Data

Dowload the weekly data and make available in the `tt` object.

```{r Load}

tt <- tt_load("2020-11-03")

```

```{r}
ikea <- tt$ikea %>%
  select(-X1) %>%
  mutate(price_usd = 0.27 * price,
         short_description = str_squish(short_description)) %>%
  add_count(category, name = "category_total")

ikea %>%
  count(category, sort = TRUE) %>%
  mutate(category = fct_reorder(category, n)) %>%
  ggplot(aes(n, category)) +
  geom_col() +
  labs(x = "# of items",
       y = "",
       title = "Most common categories of IKEA items")
```

```{r}
library(glue)

ikea %>%
  mutate(category = glue("{ category } ({ category_total })"),
         category = fct_reorder(category, price_usd)) %>%
  ggplot(aes(price_usd, category)) +
  geom_boxplot() +
  # geom_jitter(width = 0, height = .1, alpha = .25) +
  scale_x_log10(labels = dollar) +
  labs(x = "Price (USD)",
       y = "",
       title = "How much do items in each category cost?")
```

```{r}
library(ggridges)

ikea %>%
  mutate(category = glue("{ category } ({ category_total })"),
         category = fct_reorder(category, price_usd)) %>%
  ggplot(aes(price_usd, category)) +
  geom_density_ridges() +
  # geom_jitter(width = 0, height = .1, alpha = .25) +
  scale_x_log10(labels = dollar) +
  labs(x = "Price (USD)",
       y = "",
       title = "How much do items in each category cost?")
```

```{r}
ikea %>%
  mutate(category = glue("{ category } ({ category_total })"),
         category = fct_reorder(category, price_usd)) %>%
  ggplot(aes(price_usd, category, fill = other_colors)) +
  geom_density_ridges(alpha = .5) +
  # geom_jitter(width = 0, height = .1, alpha = .25) +
  scale_x_log10(labels = dollar) +
  labs(x = "Price (USD)",
       y = "",
       title = "How much do items in each category cost?")
```

If we were building a predictive model, we'd probably include both category and other_colors

```{r}
ikea %>%
  mutate(name = fct_lump(name, 20)) %>%
  filter(name != "Other") %>%
  count(name, category, sort = TRUE) %>%
  mutate(name = fct_reorder(name, n, sum),
         category = fct_reorder(category, n, sum)) %>%
  ggplot(aes(n, name, fill = category)) +
  geom_col() +
  scale_fill_discrete(guide = guide_legend(reverse = TRUE)) +
  labs(x = "# of items",
       y = "Name of item")
```

```{r}
ikea %>%
  separate(short_description,
           c("main_description", "rest"),
           sep = ", ",
           extra = "merge",
           fill = "right",
           remove = FALSE) %>%
  extract(rest, "description_cm", "([\\d\\-xX]+) cm", remove = FALSE) %>%
  unite(category_and_description, category, main_description, sep = " - ") %>%
  count(category_and_description, sort = TRUE)
```

### Volume

```{r}
ikea_volume <- ikea %>%
  mutate(volume_m3 = depth * height * width / 1e6) %>%
  filter(!is.na(volume_m3),
         volume_m3 >= .001) %>%
  arrange(desc(volume_m3)) %>%
  add_count(category, name = "category_total")

ikea_volume %>%
  arrange(desc(volume_m3))

ikea_volume %>%
  mutate(category = glue("{ category } ({ category_total })"),
         category = fct_reorder(category, volume_m3)) %>%
  ggplot(aes(volume_m3, category)) +
  geom_boxplot() +
  # geom_jitter(width = 0, height = .1, alpha = .25) +
  scale_x_log10() +
  labs(x = "Volume of furniture (cubic meters)",
       y = "",
       title = "How much space do items in each category take up?")
```

What is the highest "price per cubic meter"?

```{r}
ikea_volume %>%
  mutate(category = fct_lump(category, 6)) %>%
  ggplot(aes(volume_m3, price_usd, color = category)) +
  geom_point() +
  geom_smooth(method = "lm") +
  scale_x_log10() +
  scale_y_log10()

ikea_volume %>%
  mutate(dollar_per_m3 = price_usd / volume_m3) %>%
  arrange(desc(dollar_per_m3)) %>%
  View()
```

```{r}
ikea %>%
  group_by(designer) %>%
  summarize(n_items = n(),
            n_names = n_distinct(name),
            n_category = n_distinct(category)) %>%
  arrange(desc(n_names))
```

```{r}
library(broom)

ikea_volume %>%
  mutate(category = fct_relevel(category, "Tables & desks")) %>%
  lm(log2(price_usd) ~ log2(volume_m3) + category + other_colors, data = .) %>%
  tidy(conf.int = TRUE) %>%
  filter(term != "(Intercept)") %>%
  mutate(term = ifelse(term == "log2(volume_m3)", "Item volume (doubling)", term),
         term = str_remove(term, "^category")) %>%
  mutate(term = fct_reorder(term, estimate)) %>%
  ggplot(aes(estimate, term)) +
  geom_point() +
  geom_errorbarh(aes(xmin = conf.low, xmax = conf.high), height = .1) +
  geom_vline(xintercept = 0, color = "red", lty = 2) +
  labs(x = "Impact on price (relative to Tables & desks)",
       y = "",
       title = "What objects are unusually expensive/inexpensive relative to volume?")
```