np.concatenate() for joining arrays in NumPy - Mini Project: Build & Apply

Joining Arrays Using np.concatenate()

📖 Scenario: Imagine you have two lists of daily temperatures from two different cities. You want to combine these lists into one to analyze the overall temperature trend.

🎯 Goal: Learn how to use np.concatenate() to join two numpy arrays into one array.

📋 What You'll Learn

Create two numpy arrays with exact values

Create a variable to hold the combined array

Use np.concatenate() to join the arrays

Print the combined array

💡 Why This Matters

🌍 Real World

Joining arrays is useful when combining data from multiple sources, like merging temperature readings from different cities to analyze overall weather patterns.

💼 Career

Data scientists often need to combine datasets before analysis. Knowing how to join arrays efficiently is a key skill in data preparation.

1

Create two numpy arrays

Import numpy as np and create two numpy arrays called city1_temps and city2_temps with these exact values: [20, 22, 19] and [25, 24, 23] respectively.

NumPy

import numpy as np
# Create city1_temps and city2_temps arrays
# Your code here

Need a hint?

Use np.array() to create numpy arrays from lists.

2

Create a variable for the combined array

Create a variable called combined_temps to hold the joined array.

NumPy

import numpy as np
city1_temps = np.array([20, 22, 19])
city2_temps = np.array([25, 24, 23])
# Create combined_temps variable
# Your code here

Need a hint?

Just create the variable first. You will assign the joined array in the next step.

3

Join the arrays using np.concatenate()

Use np.concatenate() with a list containing city1_temps and city2_temps to assign the joined array to combined_temps.

NumPy

import numpy as np
city1_temps = np.array([20, 22, 19])
city2_temps = np.array([25, 24, 23])
combined_temps = None
# Use np.concatenate() to join city1_temps and city2_temps
# Your code here

Need a hint?

Pass a list of arrays to np.concatenate() to join them.

4

Print the combined array

Print the variable combined_temps to display the joined array.

NumPy

import numpy as np
city1_temps = np.array([20, 22, 19])
city2_temps = np.array([25, 24, 23])
combined_temps = np.concatenate([city1_temps, city2_temps])
# Print combined_temps
# Your code here

Need a hint?

Use print(combined_temps) to show the result.