Import Data

 ikea <- read_csv('https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2020/2020-11-03/ikea.csv')
## New names:
## Rows: 3694 Columns: 14
## ── Column specification
## ──────────────────────────────────────────────────────── Delimiter: "," chr
## (7): name, category, old_price, link, other_colors, short_description, d... dbl
## (6): ...1, item_id, price, depth, height, width lgl (1): sellable_online
## ℹ Use `spec()` to retrieve the full column specification for this data. ℹ
## Specify the column types or set `show_col_types = FALSE` to quiet this message.
## • `` -> `...1`
 skimr::skim(ikea)
Data summary
Name ikea
Number of rows 3694
Number of columns 14
_______________________
Column type frequency:
character 7
logical 1
numeric 6
________________________
Group variables None

Variable type: character

skim_variable n_missing complete_rate min max empty n_unique whitespace
name 0 1 3 27 0 607 0
category 0 1 4 36 0 17 0
old_price 0 1 4 13 0 365 0
link 0 1 52 163 0 2962 0
other_colors 0 1 2 3 0 2 0
short_description 0 1 3 63 0 1706 0
designer 0 1 3 1261 0 381 0

Variable type: logical

skim_variable n_missing complete_rate mean count
sellable_online 0 1 0.99 TRU: 3666, FAL: 28

Variable type: numeric

skim_variable n_missing complete_rate mean sd p0 p25 p50 p75 p100 hist
…1 0 1.00 1846.50 1066.51 0 923.25 1846.5 2769.75 3693 ▇▇▇▇▇
item_id 0 1.00 48632396.79 28887094.10 58487 20390574.00 49288078.0 70403572.75 99932615 ▇▇▇▇▇
price 0 1.00 1078.21 1374.65 3 180.90 544.7 1429.50 9585 ▇▁▁▁▁
depth 1463 0.60 54.38 29.96 1 38.00 47.0 60.00 257 ▇▃▁▁▁
height 988 0.73 101.68 61.10 1 67.00 83.0 124.00 700 ▇▂▁▁▁
width 589 0.84 104.47 71.13 1 60.00 80.0 140.00 420 ▇▅▂▁▁
data <- ikea %>%
  
  na.omit() %>%
  
  # Remove unnecessary columns and treat missing values
  select(-old_price, -link, -...1) %>%
  
  # Handle multiple designers
  separate_rows(designer, sep = "/") %>%
  
  # Convert character variables to factors
  mutate(across(where(is.character), as.factor)) %>%
  mutate(short_description = as.character(short_description)) %>%
  
  # Convert logical variables to factors
  mutate(across(where(is.logical), as.factor)) %>%
  
  # Log transform price (ensure no zero or negative values)
  mutate(price = log(price))

Explore Data

Identify good predictors

# Category
data %>% 
    ggplot(aes(price, category)) +
    geom_boxplot()

# Designer
data %>%
  
    # Tokenize description text
    unnest_tokens(output = word, input = short_description) %>%
    
    # calculate avg rent per word
    group_by(word) %>%
    summarise(price = mean(price),
              n = n()) %>%
    ungroup() %>%
    
    filter(n > 10, !str_detect(word, "\\d")) %>%
    slice_max(order_by = price, n = 10) %>%
    
    # Plot
    ggplot(aes(price, fct_reorder(word, price))) +
    geom_point() +
    
    labs(y = "Products")

EDA shortcut

# Step 1:Prepare data
#Select

#take out short description, and keep designer
data_binarize_tbl <- data %>%
    select(price, height, width, depth, category, other_colors, sellable_online) %>%
    binarize()

data_binarize_tbl %>% glimpse()
## Rows: 2,714
## Columns: 35
## $ `price__-Inf_5.84354441703136`               <dbl> 1, 1, 1, 1, 1, 1, 1, 1, 1…
## $ price__5.84354441703136_6.75693238924755     <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ price__6.75693238924755_7.52023455647463     <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ price__7.52023455647463_Inf                  <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `height__-Inf_74`                            <dbl> 0, 1, 0, 0, 0, 0, 0, 0, 0…
## $ height__74_95                                <dbl> 0, 0, 1, 1, 1, 1, 1, 0, 0…
## $ height__95_180.75                            <dbl> 1, 0, 0, 0, 0, 0, 0, 1, 1…
## $ height__180.75_Inf                           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `width__-Inf_60`                             <dbl> 1, 0, 1, 1, 1, 1, 1, 1, 1…
## $ width__60_100                                <dbl> 0, 1, 0, 0, 0, 0, 0, 0, 0…
## $ width__100_180                               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ width__180_Inf                               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `depth__-Inf_40`                             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ depth__40_48                                 <dbl> 0, 0, 1, 1, 1, 1, 1, 1, 1…
## $ depth__48_66                                 <dbl> 1, 1, 0, 0, 0, 0, 0, 0, 0…
## $ depth__66_Inf                                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category__Bar_furniture                      <dbl> 1, 1, 1, 1, 1, 1, 1, 1, 1…
## $ category__Beds                               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__Bookcases_&_shelving_units`       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__Cabinets_&_cupboards`             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category__Café_furniture                     <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category__Chairs                             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__Chests_of_drawers_&_drawer_units` <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__Children's_furniture`             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category__Nursery_furniture                  <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category__Outdoor_furniture                  <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__Sofas_&_armchairs`                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__Tables_&_desks`                   <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__TV_&_media_furniture`             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category__Wardrobes                          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `category__-OTHER`                           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ other_colors__No                             <dbl> 0, 1, 1, 1, 1, 1, 1, 1, 1…
## $ other_colors__Yes                            <dbl> 1, 0, 0, 0, 0, 0, 0, 0, 0…
## $ sellable_online__TRUE                        <dbl> 1, 1, 1, 1, 1, 1, 1, 1, 1…
## $ `sellable_online__-OTHER`                    <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0…
# Step 2: Correlate
data_corr_tbl <- data_binarize_tbl %>%
    correlate(price__7.52023455647463_Inf)

data_corr_tbl
## # A tibble: 35 × 3
##    feature  bin                               correlation
##    <fct>    <chr>                                   <dbl>
##  1 price    7.52023455647463_Inf                    1    
##  2 width    180_Inf                                 0.610
##  3 depth    66_Inf                                  0.418
##  4 width    -Inf_60                                -0.356
##  5 category Sofas_&_armchairs                       0.343
##  6 price    -Inf_5.84354441703136                  -0.335
##  7 price    6.75693238924755_7.52023455647463      -0.333
##  8 price    5.84354441703136_6.75693238924755      -0.332
##  9 category Wardrobes                               0.302
## 10 height   -Inf_74                                -0.283
## # ℹ 25 more rows
# Step 3: Plot
data_corr_tbl %>%
    plot_correlation_funnel() 
## Warning: ggrepel: 12 unlabeled data points (too many overlaps). Consider
## increasing max.overlaps

Build Models

Split data

data2 <- data %>%
    select(-other_colors)
# Split into train and test data set
set.seed(1234)
ikea_split <- rsample::initial_split(data2, prop = 0.75)
ikea_train <- training(ikea_split)
ikea_test <- testing(ikea_split)
# Specify recipe
ikea_recipe <- recipe(formula = price ~ ., data = ikea_train) %>%
  update_role(item_id, new_role = "id variable") %>%
  step_tokenize(short_description) %>%
  step_tokenfilter(short_description, max_tokens = 10) %>%  # Missing argument
  step_tfidf(short_description) %>% 
  step_other(category, name, sellable_online, designer, threshold = 0.05) %>%
  step_dummy(category, name, sellable_online, designer, one_hot = TRUE) %>%
  step_YeoJohnson(height, width, depth) %>%
  step_impute_knn(all_numeric_predictors()) # Fixes the broken pipeline

# Now, prep and juice
ikea_recipe %>% prep() %>% juice() %>% glimpse()    
## Rows: 2,035
## Columns: 32
## $ item_id                                   <dbl> 9219527, 99248380, 59157555,…
## $ depth                                     <dbl> 4.816575, 4.055862, 4.896875…
## $ height                                    <dbl> 13.192531, 15.758387, 20.498…
## $ width                                     <dbl> 5.949197, 10.244117, 8.93084…
## $ price                                     <dbl> 4.595120, 6.897705, 7.338238…
## $ tfidf_short_description_3                 <dbl> 0.000000, 1.278636, 1.278636…
## $ tfidf_short_description_bed               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_cm                <dbl> 0.0000000, 0.4441684, 0.4441…
## $ tfidf_short_description_combination       <dbl> 0.0000000, 0.0000000, 0.0000…
## $ tfidf_short_description_doors             <dbl> 0.0000000, 0.0000000, 0.0000…
## $ tfidf_short_description_seat              <dbl> 0.0000000, 0.0000000, 0.0000…
## $ tfidf_short_description_sofa              <dbl> 0.000000, 0.000000, 0.000000…
## $ tfidf_short_description_storage           <dbl> 0.0000000, 0.0000000, 0.0000…
## $ tfidf_short_description_wardrobe          <dbl> 0.000000, 0.000000, 0.000000…
## $ tfidf_short_description_with              <dbl> 0.0000000, 0.0000000, 0.0000…
## $ category_Beds                             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category_Bookcases...shelving.units       <dbl> 0, 1, 0, 0, 1, 0, 0, 0, 0, 1…
## $ category_Cabinets...cupboards             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category_Chairs                           <dbl> 1, 0, 0, 0, 0, 0, 0, 0, 1, 0…
## $ category_Chests.of.drawers...drawer.units <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category_Sofas...armchairs                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category_Wardrobes                        <dbl> 0, 0, 1, 0, 0, 0, 0, 1, 0, 0…
## $ category_other                            <dbl> 0, 0, 0, 1, 0, 1, 1, 0, 0, 0…
## $ name_BESTÅ                                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ name_PAX                                  <dbl> 0, 0, 0, 0, 0, 0, 0, 1, 0, 0…
## $ name_other                                <dbl> 1, 1, 1, 1, 1, 1, 1, 0, 1, 1…
## $ sellable_online_TRUE.                     <dbl> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1…
## $ sellable_online_other                     <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ designer_Ehlén.Johansson                  <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ designer_IKEA.of.Sweden                   <dbl> 1, 1, 1, 0, 0, 1, 1, 0, 1, 0…
## $ designer_Ola.Wihlborg                     <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ designer_other                            <dbl> 0, 0, 0, 1, 1, 0, 0, 1, 0, 1…
# Specify model
xgboost_spec <- 
  boost_tree(trees = tune(), min_n = tune(), mtry = tune(), learn_rate = tune())%>% 
  set_mode("regression") %>% 
  set_engine("xgboost") 

# Combine recipe and model using workflow
xgboost_workflow <- 
  workflow() %>% 
  add_recipe(ikea_recipe) %>% 
  add_model(xgboost_spec) 

# Create cross-validation folds
set.seed(2345)
ikea_cv <- vfold_cv(ikea_train, v = 5)

# Tune hyperperameters
set.seed(3456)
xgboost_tune <-
  tune_grid(xgboost_workflow, 
            resamples = ikea_cv, 
            grid = 10)
## i Creating pre-processing data to finalize unknown parameter: mtry