ArtStudies/M2/Clustering In Practice/Encoding.Rmd

```{r}
library(caret)
library(dplyr)
```

# One Hot Encoding

```{r}
df <- data.frame(
  team = c('A', 'A', 'B', 'B', 'B', 'B', 'C', 'C'),
  points = c(25, 12, 15, 14, 19, 23, 25, 29)
)

dummies <- dummyVars(~team + points, data = df)
one_hot_data <- predict(dummies, newdata = df)

one_hot_data
```

# Target Encoding

```{r}
train <- data.frame(
  target = c(10, 20, 15),
  cat_col1 = c('city1', 'city2', 'city1'),
  cat_col2 = c('james', 'adam', 'charles')
)

global_mean <- mean(train$target)
alpha <- 10

target_encoding <- train %>%
  group_by(cat_col1) %>%
  summarise(
    n = n(),
    sum_target = sum(target),
    cat_col1_te = (sum_target + (alpha * global_mean)) / (n + alpha),
    .groups = "drop"
  ) %>%
  select(cat_col1, cat_col1_te)

train <- train %>% left_join(target_encoding, by = "cat_col1")
```

# Frequential Encoding


```{r}
df <- data.frame(
  color = c('blue', 'red', 'blue', 'green'),
  value = c(10, 20, 10, 30)
)
```