Is there a better way of writing v = (v == 0 ? 1 : 0); [closed]

Is there a better way of writing v = (v == 0 ? 1 : 0); [closed]

I want to toggle a variable between 0 and 1. If it’s 0 I want to set it to 1, else if it’s 1 I want to set it to 0.
This is such a fundamental operation that I write so often I’d like to investigate the shortest, clearest possible way of doing it. Here’s my best so far:
v = (v == 0 ? 1 : 0);

Can you improve on this?
Edit: the question is asking how to write the above statement in the fewest characters while retaining clarity – how is this ‘not a real question’? This wasn’t intended to be a code-golf exercise, though some interesting answers have come out of people approaching it as golf – it’s nice to see golf being used in a constructive and thought-provoking manner.


Solution 1:

You can simply use:

v = 1 - v;

This of course assumes that the variable is initialised properly, i.e. that it only has the value 0 or 1.

Another method that is shorter but uses a less common operator:

v ^= 1;


To be clear; I never approached this question as code golf, just to find a short way of doing the task without using any obscuring tricks like side effects of operators.

Solution 2:

Since 0 is a false value and 1 is a true value.

v = (v ? 0 : 1);

If you are happy to use true and false instead of numbers

v = !v;

or if they must be numbers:

v = +!v; /* Boolean invert v then cast back to a Number */

Solution 3:

v = (v + 1) % 2 and if you need to cycle through more values just change 2 for (n + 1). Say you need to cycle 0,1,2 just do v = (v + 1) % 3.

Solution 4:

You could write a function for it and use it like:

v = inv(v)

Solution 5:

If you don’t care about any possibility other than 1:

v = v ? 0 : 1;

In the above case, v will end up being 1 if v is 0, false, undefined or null. Take care using this kind of approach – v will be 0 even if v is “hello world”.

Solution 6:

Lines like v = 1 - v, or v ^= 1 or v= +!v will all get the job done, but they constitute what I would refer to as hacks. These are not beautiful lines of code, but cheap tricks to have the intended effect. 1 - v does not communicate “toggle the value between 0 and 1”. This makes your code less expressive and introduces a place (albeit a small one) where another developer will have to parse your code.

Having instead a function like v = toggle(v) communicates the intent at the quickest glance.