np.in1d() for membership testing in NumPy - Mini Project: Build & Apply

Using np.in1d() for Membership Testing

📖 Scenario: You work in a store that tracks product IDs. You want to check which products from a new shipment are already in your current inventory.

🎯 Goal: Build a small program that uses np.in1d() to find which product IDs from the shipment are already in the inventory.

📋 What You'll Learn

Create two numpy arrays: one for current inventory product IDs and one for new shipment product IDs.

Create a variable to store the membership test result using np.in1d().

Print the boolean array showing which shipment products are in the inventory.

💡 Why This Matters

🌍 Real World

Stores and warehouses often need to check if new products are already in stock to avoid duplicates or manage inventory.

💼 Career

Data analysts and inventory managers use membership testing to clean and filter product data efficiently.

1

Create numpy arrays for inventory and shipment

Import numpy as np. Create a numpy array called inventory with these product IDs: 101, 102, 103, 104. Create another numpy array called shipment with these product IDs: 102, 105, 101, 107.

NumPy

import numpy as np
# Create the inventory and shipment arrays
# Your code here

Need a hint?

Use np.array() to create arrays with the exact product IDs given.

2

Create a variable for membership test

Create a variable called in_inventory that uses np.in1d() to check which product IDs in shipment are also in inventory.

NumPy

import numpy as np
inventory = np.array([101, 102, 103, 104])
shipment = np.array([102, 105, 101, 107])
# Use np.in1d() to check membership
# Your code here

Need a hint?

Use np.in1d(shipment, inventory) to get a boolean array.

3

Print the membership result

Print the variable in_inventory to show which shipment products are in the inventory.

NumPy

import numpy as np
inventory = np.array([101, 102, 103, 104])
shipment = np.array([102, 105, 101, 107])
in_inventory = np.in1d(shipment, inventory)
# Print the in_inventory array
# Your code here

Need a hint?

Use print(in_inventory) to display the boolean array.

4

Filter shipment products that are in inventory

Create a variable called products_in_inventory that uses shipment[in_inventory] to get the product IDs from shipment that are in inventory. Then print products_in_inventory.

NumPy

import numpy as np
inventory = np.array([101, 102, 103, 104])
shipment = np.array([102, 105, 101, 107])
in_inventory = np.in1d(shipment, inventory)
print(in_inventory)
# Filter shipment products that are in inventory
# Your code here

Need a hint?

Use boolean indexing: shipment[in_inventory] to get matching products.