What is the random State in the train test split?

In the context of Python programming language, the random State parameters in the train test split function are used to control the shuffling process before splitting the data into the training and also testing the data. By setting the random State to a fixed value, you can ensure that the same split would be generated whenever you run the code. It would make your results reproducible.

Influence on model evaluation

Setting the random State would ensure that the training and testing sets should be always the same each time when you run the code. This particular consistency would allow you to more reliable model evaluation and also the comparison. Without a fixed random State, the data split would be random on each implementation, which would lead you to different training and also testing sets which could result in varying the performance metrics. This variability can make it challenging to assess the true performance of your particular model and compare the different models or even Configuration accurately.

Here is an example given that would demonstrate how you can use train test split with and also without the random State parameters.

From sklearn.model_selection import train_test_split

From sklearn.datasets import load_iris

Import numpy as np

# Load sample dataset

Data = load_iris()

X = data.data

Y = data.target

# Splitting without random_state

X_train1, X_test1, y_train1, y_test1 = train_test_split(X, y, test_size=0.2)

X_train2, X_test2, y_train2, y_test2 = train_test_split(X, y, test_size=0.2)

# Splitting with random_state

X_train3, X_test3, y_train3, y_test3 = train_test_split(X, y, test_size=0.2, random_state=42)

X_train4, X_test4, y_train4, y_test4 = train_test_split(X, y, test_size=0.2, random_state=42)

# Comparing results

Print(“Without random_state:”)

Print(“First split, Training set class distribution:”, np.bincount(y_train1))

Print(“First split, Testing set class distribution:”, np.bincount(y_test1))

Print(“Second split, Training set class distribution:”, np.bincount(y_train2))

Print(“Second split, Testing set class distribution:”, np.bincount(y_test2))

Print(“

With random_state:”)

Print(“First split, Training set class distribution:”, np.bincount(y_train3))

Print(“First split, Testing set class distribution:”, np.bincount(y_test3))

Print(“Second split, Training set class distribution:”, np.bincount(y_train4))

Print(“Second split, Testing set class distribution:”, np.bincount(y_test4))

# Comparing if the splits are the same

Print(“

Without random_state, splits are the same:”, np.array_equal(X_train1, X_train2) and np.array_equal(y_train1, y_train2))

Print(“With random_state, splits are the same:”, np.array_equal(X_train3, X_train4) and np.array_equal(y_train3, y_train4))

Without random State

Each time when you run the train test function without setting the random State, the functions would produce w different random split. This can be observed by comparing the class distribution on the training and the testing sets from the different splits which are likely to differ.

With random State

By setting the random State to a fixed value, the splits would be reproducible. The class distribution of the training and testing sets from the different splits would be identical, which would demonstrate consisting results across the runs. Thus this particular consistency is very crucial for model evaluation and also the comparison.

Output (expected)

Without random_state:

First split, Training set class distribution: [40 39 41]

First split, Testing set class