Python Libraries for Data Science

It’s kind of like having your own personal calculator that can handle all sorts of complex operations at lightning speed.

For example, let’s say you want to train a neural network model using TensorFlow. You would start by importing the library and loading in some data:

# Import TensorFlow library
import tensorflow as tf

# Import load_iris function from scikit-learn library
from sklearn.datasets import load_iris

# Load iris dataset from scikit-learn
iris = load_iris()

# Assign data and target values to variables X and y respectively
X, y = iris['data'], iris['target']

# Calculate the size of the training set by multiplying the length of X with 0.8
train_size = int(len(X) * 0.8)

# Split data into training and testing sets using the calculated train_size
X_train, X_test, y_train, y_test = X[:train_size], X[train_size:], y[:train_size], y[train_size:]

Next, you would define your neural network model using TensorFlow’s high-level API or Keras (which is a popular library built on top of TensorFlow). Here’s an example of how to create a simple feedforward neural network with one hidden layer and 10 neurons:

# Define the input shape for our model
input_shape = [4,] # 4 features (sepal length, sepal width, petal length, petal width)

# Create a sequential model using Keras' high-level API
model = tf.keras.Sequential([
    # Add the input layer with 4 neurons (one for each feature)
    tf.keras.layers.Dense(units=10, activation='relu', input_shape=input_shape), # Define a dense layer with 10 neurons and ReLU activation function, taking in the input shape of 4 features
    # Add a hidden layer with 10 neurons and ReLU activation function
    tf.keras.layers.Dense(units=10, activation='relu'), # Define a dense layer with 10 neurons and ReLU activation function
    # Add the output layer with 3 neurons (one for each class)
    tf.keras.layers.Dense(units=3, activation='softmax') # Define a dense layer with 3 neurons and softmax activation function for multi-class classification
])

Finally, you would compile and train your model using TensorFlow’s built-in optimizers and loss functions:

# Compile the model with a categorical crossentropy loss function and Adam optimization algorithm
# Use TensorFlow's built-in optimizers and loss functions to compile the model
model.compile(loss='categorical_crossentropy', optimizer=tf.keras.optimizers.Adam(), metrics=['accuracy'])

# Train the model for 10 epochs (iterations) using batch size of 32 samples per iteration
# Use the fit() function to train the model on the training data for a specified number of epochs and batch size
history = model.fit(X_train, y_train, validation_data=(X_test, y_test), epochs=10, batch_size=32)

And that’s it! You now have a trained neural network model that can classify new samples based on their features. Pretty cool, huh?

SICORPS