Questions tagged [one-hot-encoding]

One-Hot Encoding is a method to encode categorical variables to numerical data that Machine Learning algorithms can deal with. One-Hot encoding is most used during feature engineering for a ML Model. It converts categorical values into a new categorical column and assign a binary value of 1 or 0 to those columns.

Also known as Dummy Encoding, One-Hot Encoding is a method to encode categorical variables, where no such ordinal relationship exists, to numerical data that Machine Learning algorithms can deal with. One hot encoding is the most widespread approach, and it works very well unless your categorical variable takes on a large number of unique values. One hot encoding creates new, binary columns, indicating the presence of each possible value from the original data. These columns store ones and zeros for each row, indicating the categorical value of that row.

1224 questions
2
votes
5 answers

Ordinal encoding in Pandas

Is there a way to have pandas.get_dummies output the numerical representation in one column rather than a separate column for each option? Concretely, currently when using pandas.get_dummies it gives me a column for every…
mikelowry
  • 1,307
  • 4
  • 21
  • 43
2
votes
2 answers

How to handle "unseen" categorical variables with one hot encoding in sklearn

I have a training data (df_train) in which I applied 3rd polynomial to variable x1 and also one hot encoding approach to color variables. The goal is to get the coefficient for each independent variable and predict the Y (target variable) in the…
2
votes
0 answers

How to get the reference level of a factor column?

I know you can use relevel to set a value as the reference level of a factor. I want to do the opposite: given a factor column, how can I retrieve the reference value? I guess the most trivial way would be to run a regression with lm and see which…
Arturo Sbr
  • 5,567
  • 4
  • 38
  • 76
2
votes
2 answers

Python pandas: dynamic concatenation from get_dummies

having the following dataframe: import pandas as pd cars = ["BMV", "Mercedes", "Audi"] customer = ["Juan", "Pepe", "Luis"] price = [100, 200, 300] year = [2022, 2021, 2020] df_raw = pd.DataFrame(list(zip(cars, customer, price, year)),\ …
Enrique Benito Casado
  • 1,914
  • 1
  • 20
  • 40
2
votes
1 answer

How should I OneHotEncod a column of (8128 rows and) 2058 nuniques?

The title, pretty much. I just want to know the best and most efficient way to OneHotEncode a column with like 2058 nuniques. Doing a fit_transform of said column, I know I will get an array of 2058 (minus 1 when you drop first) columns. Is it the…
Anonymous Person
  • 1,437
  • 8
  • 26
  • 47
2
votes
1 answer

Python: replace multiple column values based on values present in other columns

good morning. I am trying to replace multiple column values based on values present in other columns. I am able to do this in R but I dont understand how I can do the same with python. I tried using np.where() and df.loc approach but it only allows…
xboxuser
  • 160
  • 1
  • 11
2
votes
1 answer

One hot Encoding text data in pytorch

I am wondering how to one hot encode text data in pytorch? For numeric data you could do this import torch import torch.functional as F t = torch.tensor([6,6,7,8,6,1,7], dtype = torch.int64) one_hot_vector = F.one_hot(x = t,…
imantha
  • 2,676
  • 4
  • 23
  • 46
2
votes
1 answer

pyspark explode one-hot encoded vector to each column with proper name

Applying one-hot encoding to multiple categorical column X_cat = X.select(cat_cols) str_indexer = [StringIndexer(inputCol=col, outputCol=col+"_si", handleInvalid="skip") for col in cat_cols] ohe = [OneHotEncoder(inputCol=f"{col}_si",…
haneulkim
  • 4,406
  • 9
  • 38
  • 80
2
votes
0 answers

One Hot Encoding: Avoiding dummy variable trap and process unseen data with scikit learn

I'm building a model, pretty much similiar to the well known House Price Prediction. I got to the point that I need to encode my nominal categorical variables by using scikit-learns OneHotEncoder. The so called "Dummy Variable Trap" is clear to me…
Buggy
  • 43
  • 5
2
votes
0 answers

Incremental OneHotEncoding and Target Encoding

I am working with a large tabular dataset that consists of many categorical columns. I want to train a regression model (XGBoost) in this data while using as many regressors as possible. Because of the size of data, I am using incremental training -…
Petr
  • 1,606
  • 2
  • 14
  • 39
2
votes
3 answers

Decide which category to drop in pandas get_dummies()

Let's say I have the following df: data = [{'c1':a, 'c2':x}, {'c1':b,'c2':y}, {'c1':c,'c2':z}] df = pd.DataFrame(data) Output: c1 c2 0 a x 1 b y 2 c z Now I want to use pd.get_dummies() to one hot encode the two…
TiTo
  • 833
  • 2
  • 7
  • 28
2
votes
1 answer

How to make one-hot data compatible with non one-hot?

I'm making a machine learning model to calculate game win rate on different character combination. I got error at last line using loss function. I think it's because the input is one-hot vector. The output of the model doesn't compatile with target…
2
votes
1 answer

Map classes to Pandas one hot encoding

Given the below sequence: [I, Z, S, I, I, J, N, J, I] and given the below Pandas data frame: char fricative nasal lateral labial coronal dorsal frontal I 0 0 0 0 0 0 1 J 0 0 …
2
votes
1 answer

Explanation of tf.keras.layers.CategoryEncoding output_mode='multi_hot' behavior

Question Please help understand the definition of multi hot encoding of tf.keras.layers.CategoryEncoding and the behavior of output_mode='multi_hot'. Background According to What exactly is multi-hot encoding and how is it different from…
mon
  • 18,789
  • 22
  • 112
  • 205
2
votes
1 answer

Create an sparse matrix from a list of tuples having the indexes of the column where is a 1

Problem: I have a list of tuples, which each tuple represents a column of a 2D-array and each element of the tuple represents the index of that column of the array that is a 1; the other entries that aren't in that tuple, are 0. I want to create an…