Python FTW: Under the Hood/

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Nan-reflexivity

Nan-reflexivity

We'll cover the following...

Let’s see what Python thinks about NaN and infinity.

1.

What do you think about these assignments?

Python 3.5
a = float('inf')
b = float('nan')
c = float('-iNf')  # These strings are case-insensitive
d = float('nan')

Let’s observe some behaviors in the terminal below:

Terminal 1
Terminal
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2.

Let’s explore further.

Python 3.5
x = float('nan')
y = x / x
print(y is y) # identity holds
print(y == y) # equality fails of y
print([y] == [y]) # but the equality succeeds for the list containing y

Explanation

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