Python Forum
NumPy Side Effects - HELP UNDERSTANDING - Printable Version

+- Python Forum (https://python-forum.io)
+-- Forum: Python Coding (https://python-forum.io/forum-7.html)
+--- Forum: General Coding Help (https://python-forum.io/forum-8.html)
+--- Thread: NumPy Side Effects - HELP UNDERSTANDING (/thread-29710.html)

NumPy Side Effects - HELP UNDERSTANDING - lasek723 - Sep-16-2020

I AM CURRENTLY ON CHAPTER 4 WITH DATACAMP. SO FAR, SO GOOD

HOWEVER, I AM TRYING TO UNDERSTAND THIS

Have a look at this line of code:

np.array([True, 1, 2]) + np.array([3, 4, False])
Can you tell which code chunk builds the exact same Python object? The numpy package is already imported as np, so you can start experimenting in the IPython

HOW DOES

np.array([True, 1, 2]) + np.array([3, 4, False])

=

np.array([4, 3, 0]) + np.array([0, 2, 2])

CAN SOMEONE EXPLAIN THIS IN SIMPLE TERMS PLEASE :-)

RE: NumPy Side Effects - HELP UNDERSTANDING - micseydel - Sep-16-2020

Python treats True like 1, and False like 0. Other than that, it's just summing the respective elements. It's much like this:
Output:
>>> def sum_elements(first_elements, second_elements):
...     return [x + y for x, y in zip(first_elements, second_elements)]
... 
>>> sum_elements([True, 1, 2], [3, 4, False])
[4, 5, 2]
>>> sum_elements([4, 3, 0], [0, 2, 2])
[4, 5, 2]


RE: NumPy Side Effects - HELP UNDERSTANDING - ndc85430 - Sep-17-2020

Also, please avoid writing in all caps, as it looks like you're shouting.

RE: NumPy Side Effects - HELP UNDERSTANDING - lasek723 - Sep-17-2020

(Sep-16-2020, 10:08 PM)micseydel Wrote: Python treats True like 1, and False like 0. Other than that, it's just summing the respective elements. It's much like this:
Output:
>>> def sum_elements(first_elements, second_elements):
...     return [x + y for x, y in zip(first_elements, second_elements)]
... 
>>> sum_elements([True, 1, 2], [3, 4, False])
[4, 5, 2]
>>> sum_elements([4, 3, 0], [0, 2, 2])
[4, 5, 2]

Ahhh okay. Thank you for explaining :-)