# Compact way of writing (a + b == c or a + c == b or b + c == a)

Is there a more compact or pythonic way to write the boolean expression

```    a + b == c or a + c == b or b + c == a
```

I came up with

```    a + b + c in (2*a, 2*b, 2*c)
```

but that is a little strange.

If we look at the Zen of Python, emphasis mine:

The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than right now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

The most Pythonic solution is the one that is clearest, simplest, and easiest to explain:

```    a + b == c or a + c == b or b + c == a
```

Even better, you don't even need to know Python to understand this code! It's that easy. This is, without reservation, the best solution. Anything else is intellectual masturbation.

Furthermore, this is likely the best performing solution as well, as it is the only one out of all the proposals that short circuits. If `a + b == c`, only a single addition and comparison is done.

From: stackoverflow.com/q/32085675