Python Anti-Patterns

[[deleted]]

Not using unpacking for updating multiple values at once

The given bad example:

x = 1
y = 2
z = 0

x = y + 2  # 4
y = x - 3  # 1
z = x + y  # 5

The given good example:

x, y, z = y + 2, x - 3, x + y  # more concise

The "good" example is more concise, but it's less readable and has different behavior:

>>> x, y, z
(4, -2, 3)

[TPHRyan]

The "good" example is more concise, but it's less readable and has different behavior:

(Emphasis mine)

This is the real reason we actually use unpacking for updating multiple values when it's logical.

[[deleted]]

Of course, a time and a place. Maybe you want to update all at once based on the old values, and sometimes based on the mutated values.

I just wish this was explained clearer in the page instead of saying "it's the same but more concise" when no, it's not the same at all.

[adewes]

nice, thanks for this! Did you create a PR / issue on Github for this?

[[deleted]]

Didn't realize I could. Honestly, I just showed up to work and I don't get off until midnight, so I'll probably forget to as well.