np.sign() for sign detection in NumPy - Mini Project: Build & Apply

Detecting Number Signs Using np.sign()

📖 Scenario: Imagine you have a list of daily temperature changes in degrees Celsius. Some days are warmer (positive change), some are colder (negative change), and some days have no change (zero). You want to quickly find out which days were warmer, colder, or stayed the same.

🎯 Goal: You will create a program that uses np.sign() to detect the sign of each temperature change and output the results as an array of -1, 0, or 1.

📋 What You'll Learn

Create a numpy array with exact temperature changes

Create a variable to hold the numpy array

Use np.sign() to find the sign of each number

Print the resulting sign array

💡 Why This Matters

🌍 Real World

Detecting signs of numbers is useful in finance to know if stock prices went up or down, in weather to track temperature changes, or in any data where direction matters.

💼 Career

Data scientists often need to quickly classify data points by their sign to make decisions or prepare data for further analysis.

1

Create the temperature changes array

Create a numpy array called temp_changes with these exact values: [-3, 0, 4, -1, 2, 0].

NumPy

import numpy as np
# Create the numpy array temp_changes with values [-3, 0, 4, -1, 2, 0]
# Your code here

Need a hint?

Use np.array() to create the array with the exact values.

2

Prepare to detect signs

Create a variable called signs and set it to None as a placeholder before detecting signs.

NumPy

import numpy as np

temp_changes = np.array([-3, 0, 4, -1, 2, 0])

# Create a variable signs and set it to None
# Your code here

Need a hint?

Just create the variable signs and assign None to it.

3

Detect the sign of each temperature change

Use np.sign() on the temp_changes array and assign the result to the variable signs.

NumPy

import numpy as np

temp_changes = np.array([-3, 0, 4, -1, 2, 0])

signs = None

# Use np.sign() on temp_changes and assign to signs
# Your code here

Need a hint?

Call np.sign(temp_changes) and save it in signs.

4

Print the sign detection result

Print the variable signs to display the sign of each temperature change.

NumPy

import numpy as np

temp_changes = np.array([-3, 0, 4, -1, 2, 0])

signs = np.sign(temp_changes)

# Print the signs array
# Your code here

Need a hint?

Use print(signs) to show the output.