FutureWarning: elementwise comparison failed; returning scalar, but in the future will perform elementwise comparison warning occurs when you “compare numpy array with another object obj using arr == obj.”
This warning is raised when you try to perform an elementwise comparison operation (like == or !=) between an array and an object of a different shape or type, and the comparison doesn’t behave as one might intuitively expect.
Flow diagram
Reproducing the warning
import numpy as np
np.arange(3) == np.arange(3).astype(str)
Output
FutureWarning: elementwise comparison failed; returning scalar instead,
but in the future will perform elementwise comparison
You can see that the warning you’re encountering is caused by attempting to compare two NumPy arrays with different data types. The first array (np.arange(3)
) contains integers, while the second array (np.arange(3).astype(str)
) has been cast to strings.
How to fix it
To fix the FutureWarning: elementwise comparison failed; returning scalar, but in the future will perform elementwise comparison, you can use the .astype() function to ensure that both arrays have the same data type before comparing.
You can convert a numpy array’s data type using the .astype() function.
import numpy as np
arr_1 = np.arange(3).astype(str)
arr_2 = np.arange(3).astype(str)
print(arr_1 == arr_2)
Output
[ True True True]
That’s it!
Krunal Lathiya is a seasoned Computer Science expert with over eight years in the tech industry. He boasts deep knowledge in Data Science and Machine Learning. Versed in Python, JavaScript, PHP, R, and Golang. Skilled in frameworks like Angular and React and platforms such as Node.js. His expertise spans both front-end and back-end development. His proficiency in the Python language stands as a testament to his versatility and commitment to the craft.