One Hot Encode Algorithm

The One Hot Encode Algorithm is a widely used technique in machine learning and natural language processing for transforming categorical data into a numerical format that can be easily understood and processed by machine learning models. This method is particularly useful when dealing with nominal or unordered categories, such as colors, countries, or product types. In one hot encoding, each unique category in the dataset is represented as a binary vector, where the length of the vector is equal to the number of distinct categories. Each element in the vector corresponds to a specific category, and the value of the element is set to 1 if the given data point belongs to that category, and 0 otherwise. The main advantage of using the one hot encoding technique is that it eliminates the ordinal relationships between categories that might not exist, preventing machine learning algorithms from assuming any incorrect or arbitrary hierarchies between these categories. For example, consider a dataset containing the colors red, blue, and green. Assigning numerical values, such as 1 for red, 2 for blue, and 3 for green might lead the algorithm to assume that green is somehow "greater" than blue or red, which is not true in our context. By using one hot encoding, we create three separate binary features for red, blue, and green, avoiding any false assumptions about the relationship between the categories. However, one downside of this approach is that it can lead to high-dimensional data, especially when dealing with a large number of distinct categories, which may require more memory and computational resources to process.
library(tidyverse)
#divide data into train and test in 70% and 30%
ind<-sample(2,nrow(diamonds),replace = T,prob = c(0.7,0.3))
train.set<-diamonds[ind==1,]
test.set<-diamonds[ind==2,]

# one hot encode using model.matrix(built-in function)
#along with %>%, select_if, bind_cols, as.tibble in dplyr and tibble
train<-bind_cols(select_if(train.set,is.numeric),model.matrix(~cut-1,train.set) %>% as.tibble(),
                model.matrix(~color-1,train.set) %>% as.tibble(),model.matrix(~clarity-1,train.set) %>% as.tibble())
test<-bind_cols(select_if(test.set,is.numeric),model.matrix(~cut-1,test.set) %>% as.tibble(),
                model.matrix(~color-1,test.set) %>% as.tibble(),model.matrix(~clarity-1,test.set) %>% as.tibble())

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