I thought I might be able to find more fuel for my anti-python argument by investigating exactly what objects are equal to each other (generate a truth table). Also, I wanted to be confident of what values are considered True or False.

The one best practice related to this – that a colleague taught me – is use `x is None`

instead of use `if x == None: ...`

because None could be equal to any object depending on its implementation of `__eq__`

.

The python truth table is actually, very reasonable.

This is a pure and beautiful sight compared to to Javascript or PHP. It is a little surprising to me that `[] == []`

since I would expect them to be two different list instances, but I would expect equality for `(,) = (,)`

(identical tuples).

There are a few nuances when considering truthiness, however. If you’ve got code that reads `if x: ...`

The following values for x are treated as false:

`None`

`False`

- zero of any numeric type. Like these:
`0`

,`0L`

,`0.0`

,`0j`

. - any empty string, tuple, or array.
`''`

,`()`

,`[]`

. - an empty dictionary, for example,
`{}`

. - instances of user-defined classes, if the class defines a
`__nonzero__()`

or`__len__()`

method and that method returns the integer`0`

or boolean value`False`

Everything else is truthy (considered equal to True).

Here’s the code I used to generate the tables above.

## What do you think?