How can I check if my python object is a number?
In Java the numeric types all descend from Number so I would use
(x instanceof Number).
What is the python equivalent?
Answer
Test if your variable is an instance of numbers.Number:
>>> import numbers
>>> import decimal
>>> [isinstance(x, numbers.Number) for x in (0, 0.0, 0j, decimal.Decimal(0))]
[True, True, True, True]
This uses ABCs and will work for all built-in number-like classes, and also for all third-party classes if they are worth their salt (registered as subclasses of the Number ABC).
However, in many cases you shouldn't worry about checking types manually - Python is duck typed and mixing somewhat compatible types usually works, yet it will barf an error message when some operation doesn't make sense (4 - "1"), so manually checking this is rarely really needed. It's just a bonus. You can add it when finishing a module to avoid pestering others with implementation details.
This works starting with Python 2.6. On older versions you're pretty much limited to checking for a few hardcoded types.