Click here for the data. Goal: Predict future price of IKEA furniture

Import data

ikea <- readr::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 %>%
  
  # Handle missing values
  filter(!is.na(height), !is.na(width), !is.na(depth)) %>%
  
  # Convert all character variables to factors for machine learning compatibility
  mutate(across(where(is.character), as.factor)) %>% 
  
      mutate(across(is.logical, as.factor)) %>%


  # Handle multiple designers by splitting them into separate rows
  separate_rows(designer, sep = "/") %>%

  # Remove unnecessary columns
  select(-...1, -link, -old_price, -designer, -name) %>%
  
  # Log transform price to address skewness
  mutate(price = log(price))
## Warning: There was 1 warning in `mutate()`.
## ℹ In argument: `across(is.logical, as.factor)`.
## Caused by warning:
## ! Use of bare predicate functions was deprecated in tidyselect 1.1.0.
## ℹ Please use wrap predicates in `where()` instead.
##   # Was:
##   data %>% select(is.logical)
## 
##   # Now:
##   data %>% select(where(is.logical))

Explore Data - Identifying good predictors

# Step 1: Prepare data by binarising data
binarized_table <- data %>%
    select(-item_id, -short_description) %>%
    binarize()

binarized_table %>% glimpse()
## Rows: 2,714
## Columns: 35
## $ 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…
## $ `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…
## $ 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…
## $ 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…
## $ `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…
## $ `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…
# Correlate
corr_tbl <- binarized_table %>%
    correlate(price__7.52023455647463_Inf)

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 Correlation Funnel
corr_tbl %>%
    plot_correlation_funnel()
## Warning: ggrepel: 12 unlabeled data points (too many overlaps). Consider
## increasing max.overlaps

Preprocessing - Recipe Improvements

ikea_recipe_improved <- recipe(price ~ ., data = data) %>%
  update_role(item_id, new_role = "id variable") %>%
  step_tokenize(short_description) %>%
  step_tokenfilter(short_description, max_tokens = 150) %>%  # Adjust max_tokens
  step_tfidf(short_description) %>%
  step_other(category, threshold = 0.05) %>%  # More aggressive threshold
    step_novel(all_nominal_predictors()) %>%
  step_dummy(all_nominal_predictors(), one_hot = TRUE) %>%
  step_YeoJohnson(all_numeric_predictors())  # Normalize skewed variables

ikea_recipe_improved %>% prep() %>% juice() %>% glimpse()
## Rows: 2,714
## Columns: 170
## $ item_id                                   <dbl> 80155205, 30180504, 10122647…
## $ depth                                     <dbl> 4.415739, 4.641769, 4.286541…
## $ height                                    <dbl> 13.841936, 9.122162, 13.2276…
## $ width                                     <dbl> 6.309291, 6.780073, 5.455728…
## $ price                                     <dbl> 4.234107, 5.416100, 5.843544…
## $ tfidf_short_description_1                 <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_10                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_100x60x236        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_120               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_120x42x240        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_120x42x74         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_140x200           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_143               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_147x147           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_150x44x236        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_150x58x201        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_150x60x201        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_150x60x236        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_150x66x236        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_160x30x202        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_160x30x237        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_165x55x216        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_180x42x74         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_2                 <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_200x44x236        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_200x60x236        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_200x66x236        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_223x80x84         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_250x60x236        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_25x51x70          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_3                 <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_300x60x236        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_35x35x35          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_4                 <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_40x30x106         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_41x101            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_41x61             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_5                 <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_6                 <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_60x22x202         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_60x50x128         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_60x50x192         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_61x101            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_63                <dbl> 0.0000000, 0.0000000, 0.8787…
## $ tfidf_short_description_74                <dbl> 0.7582519, 0.0000000, 0.0000…
## $ tfidf_short_description_75                <dbl> 0.0000000, 0.0000000, 0.0000…
## $ tfidf_short_description_76                <dbl> 0.000000, 0.000000, 0.000000…
## $ tfidf_short_description_77x147            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_8                 <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_80x200            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_80x30x202         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_89x30x124         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_90                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_90x200            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_90x79x102         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_99x44x56          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_add               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_and               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_armchair          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_armrest           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_armrests          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_backrest          <dbl> 0.6416913, 0.0000000, 0.6416…
## $ tfidf_short_description_backrests         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_bar               <dbl> 0.5823944, 0.0000000, 0.5823…
## $ tfidf_short_description_baskets           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_bed               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_bedside           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_bench             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_bookcase          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_box               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_cabinet           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_cabinets          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_castors           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_chair             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_chaise            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_changing          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_chest             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ `tfidf_short_description_children's`      <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_clothes           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_cm                <dbl> 0.12453381, 0.17345325, 0.12…
## $ tfidf_short_description_combination       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_corner            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_cover             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_cushion           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_day               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_desk              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_display           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_door              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_doors             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_drawer            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_drawers           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_dressing          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_drs               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_easy              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_extension         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_feet              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_foldable          <dbl> 0.0000000, 0.0000000, 0.0000…
## $ tfidf_short_description_folding           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_footstool         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_for               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_frame             <dbl> 0.0000000, 0.0000000, 0.0000…
## $ tfidf_short_description_glass             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_headboard         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_high              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_highchair         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_in                <dbl> 0.0000000, 0.0000000, 0.0000…
## $ tfidf_short_description_inserts           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_junior            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_leg               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_legs              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_lock              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_longue            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_mattresses        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_media             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_mesh              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_modular           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_module            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_mounted           <dbl> 0.0000000, 0.9667203, 0.0000…
## $ tfidf_short_description_of                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_on                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_outdoor           <dbl> 0.0000000, 0.0000000, 0.0000…
## $ tfidf_short_description_panel             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_plinth            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_rail              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_rails             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_seat              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_section           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_sections          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_shelf             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_shelves           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_shelving          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_side              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_sliding           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_smart             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_sofa              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_step              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_stool             <dbl> 0.5269921, 0.0000000, 0.5269…
## $ tfidf_short_description_storage           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_table             <dbl> 0.000000, 0.950408, 0.000000…
## $ tfidf_short_description_three             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_top               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_toy               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_tray              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_triple            <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_tv                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_two               <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_underframe        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_unit              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_upright           <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_ut                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_w                 <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_wall              <dbl> 0.0000000, 0.8271747, 0.0000…
## $ tfidf_short_description_wardrobe          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_wire              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ tfidf_short_description_with              <dbl> 0.2918635, 0.0000000, 0.2918…
## $ category_Beds                             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category_Bookcases...shelving.units       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category_Cabinets...cupboards             <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category_Chairs                           <dbl> 0, 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, 0…
## $ category_Sofas...armchairs                <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category_Wardrobes                        <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ category_other                            <dbl> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1…
## $ category_new                              <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ sellable_online_FALSE.                    <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ sellable_online_TRUE.                     <dbl> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1…
## $ sellable_online_new                       <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ other_colors_No                           <dbl> 0, 1, 1, 1, 1, 1, 1, 1, 1, 1…
## $ other_colors_Yes                          <dbl> 1, 0, 0, 0, 0, 0, 0, 0, 0, 0…
## $ other_colors_new                          <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0…

Data Splitting and Cross-Validation Setup

set.seed(1234)
ikea_split <- initial_split(data, prop = 0.75)
ikea_train <- training(ikea_split)
ikea_test <- testing(ikea_split)

set.seed(2345)
ikea_cv <- vfold_cv(ikea_train, v = 5)

Model Specification (XGBoost, Random Forest, SVM)

# XGBoost Model
xgboost_spec <- boost_tree(trees = tune(), min_n = tune(), mtry = tune(), learn_rate = tune()) %>%
  set_mode("regression") %>%
  set_engine("xgboost")

# Random Forest Model
rf_spec <- rand_forest(trees = tune(), min_n = tune(), mtry = tune()) %>%
  set_mode("regression") %>%
  set_engine("ranger")

# SVM Model
svm_spec <- svm_rbf(cost = tune(), rbf_sigma = tune()) %>%
  set_mode("regression") %>%
  set_engine("kernlab")

# Create workflows
xgboost_workflow <- workflow() %>%
  add_recipe(ikea_recipe_improved) %>%
  add_model(xgboost_spec)

rf_workflow <- workflow() %>%
  add_recipe(ikea_recipe_improved) %>%
  add_model(rf_spec)

svm_workflow <- workflow() %>%
  add_recipe(ikea_recipe_improved) %>%
  add_model(svm_spec)

Evaluate Models

# Collect metrics for each model
xgboost_results <- collect_metrics(xgboost_tune)
rf_results <- collect_metrics(rf_tune)
svm_results <- collect_metrics(svm_tune)

# Compare RMSE and R-squared for all models
bind_rows(xgboost_results, rf_results, svm_results) %>%
  filter(.metric == "rmse") %>%
  arrange(mean)
## # A tibble: 170 × 12
##     mtry trees min_n learn_rate .metric .estimator  mean     n std_err .config  
##    <int> <int> <int>      <dbl> <chr>   <chr>      <dbl> <int>   <dbl> <chr>    
##  1     8  1529    36     0.0720 rmse    standard   0.387     5 0.00787 Preproce…
##  2    NA    NA    NA    NA      rmse    standard   0.396     5 0.0125  Preproce…
##  3     9   466    11     0.0210 rmse    standard   0.443     5 0.0116  Preproce…
##  4     9  1000     2    NA      rmse    standard   0.470     5 0.00942 Preproce…
##  5     9   500     2    NA      rmse    standard   0.470     5 0.0102  Preproce…
##  6     9  1500     2    NA      rmse    standard   0.471     5 0.0104  Preproce…
##  7     9  2000     2    NA      rmse    standard   0.471     5 0.0102  Preproce…
##  8     9   500    11    NA      rmse    standard   0.476     5 0.0102  Preproce…
##  9     9  1500    11    NA      rmse    standard   0.477     5 0.00988 Preproce…
## 10     9  2000    11    NA      rmse    standard   0.478     5 0.00943 Preproce…
## # ℹ 160 more rows
## # ℹ 2 more variables: cost <dbl>, rbf_sigma <dbl>

Finalize best model and predict

# Select best performing model (e.g., XGBoost)
xgboost_best <- finalize_workflow(xgboost_workflow, select_best(xgboost_tune, metric = "rmse"))

# Fit the final model on the entire training set and test it
ikea_fit <- last_fit(xgboost_best, ikea_split)

# Evaluate on test data
test_metrics <- collect_metrics(ikea_fit)
test_predictions <- collect_predictions(ikea_fit)

# Plot actual vs predicted prices
test_predictions %>%
  ggplot(aes(x = price, y = .pred)) +
  geom_point(alpha = 0.3, color = "midnightblue") +
  geom_abline(lty = 2, color = "gray50") +
  coord_fixed() +
  labs(title = "Predicted vs Actual Prices (Test Data)", x = "Actual Price (log-transformed)", y = "Predicted Price")

# Extract RMSE, R-squared, and variance explained
rmse_value <- test_metrics %>%
  filter(.metric == "rmse") %>%
  pull(".estimate")  # Corrected: ".estimate" is the correct column

rsq_value <- test_metrics %>%
  filter(.metric == "rsq") %>%
  pull(".estimate")  # Corrected: ".estimate" is the correct column

variance_explained <- rsq_value * 100

# Print the values
print(paste("RMSE:", rmse_value))
## [1] "RMSE: 0.379546001213468"
print(paste("R-squared:", rsq_value))
## [1] "R-squared: 0.903283387235221"
print(paste("Variance Explained (%):", variance_explained))
## [1] "Variance Explained (%): 90.3283387235221"

Conclusion of Result

The final model for predicting IKEA furniture prices performed very well, with an RMSE of 0.3795 and an R-squared of 0.9033. This means the model explains about 90.33% of the price variations, showing that it makes accurate predictions.

Several improvements helped boost performance, including:

The low RMSE means the predicted prices are very close to actual prices, and the high R-squared shows the model captures important price patterns. While there is always room for small improvements, this model is rather reliable for predicting IKEA furniture prices.