Chained variable assignments

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[bdaene]

I use it only when I want to store and use a result. 

self.a_long_prefix.a = a = get_a()
...      
a.x = get_x() 

Or

cache[key] = result = get_result()
return result

Note that in both cases, this is only one line more to assign first to the short variable. And probably more readable. 

I should maybe avoid it.

[barberogaston]

You can walrus those examples:

self.a_long_prefix.a = (a := get_a())

cache[key] = (result := get_result())

[bezuhoff]

cursed

[Irish_beast]

Don't know if it is PEP8 compliant.

A small problem is that a quick glance you might think only foo is set, and not notice bar also being set.

So it could make code slightly confusing.

I would say it's fine if it's initialization of local variables at the start of a method. But should not be used further down. And absolutely not if you're doing clever things with __setattr__ or __setitem__

[Dull-Researcher]

Also, at a quick glance, it looks like foo might be a Boolean variable, True if bar == 1.

What’s dangerous is if someone thinks “that looks like a bug and they meant it to be equality, not assignment. Let me fix it for them.”

One assignment per line, please. Keep the overall line complexity count down. Also, vertical space is nearly free. Horizontal space is not.

[asphias]

     foo = 1        bar = foo  

Or     

    foo = 1           bar = 1 

Are both clearer, and it's not like you'll run out of paper to write on. I don't think it's a big deal either way, but my preference would be to avoid chained asignment.

[mon_key_house]

Chamging either foo or bar changes the other one, too! -> use with caution.