CODEWITHSUNDEEP
pythonvariables
contactlight
contactlight

Reputation: 3

Assign variables in one line in Python

Is it ok to assign variables like this in Python?

mean, variance, std = 0

Upvotes: -1

Views: 966

Answers (2)

mrvol
mrvol

Reputation: 2983

Did you try it?

>>> mean, variance, std, max, min, sum = 0
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'int' object is not iterable

It must be:

mean = variance = std = max_ = min_ = sum_ = 0

Unless you have a deal with int, bool it is ok.

You can check it easily:

>>> id(mean) == id(variance)
True
>>> id(mean) == id(variance)
True
>>> mean = 1
>>> id(mean) == id(variance)
False

But:

>>> mean = variance = std = max_ = min_ = sum_ = {}
>>> mean['a'] = '1'
>>> variance['a']
'1'
>>> del mean['a']
>>> variance
{}
>>>

They all are the same. And please don't use sum, min, max as var names - it is a reserved word in Python.

Upvotes: 0

Registered User
Registered User

Reputation: 8395

There are a few options for one-liners:

This version is only safe if assigning immutable object values like int, str, and float. Don't use this with mutable objects like list and dict objects.

mean = variance = std = max = min = sum = 0

Another option is a bit more verbose and does not have issues with mutable objects. You can raise ValueError errors if you don't have the same number of objects on each side.

mean, variance, std, max, min, sum = 0, 0, 0, 0, 0, 0

Upvotes: 2

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