CODEWITHSUNDEEP
variablesnaming
Trap
Trap

Reputation: 12372

How to correctly name a variable which represents a value of 1 - n?

It obviously depends on the context you are using them in but, I was wondering if there is a universally accepted way to name such variables, or at least in a mathematical context.

I've often seen:

float k         = someValue;
float oneMinusK = 1 - k;

...which seems as descriptive as much as meaningless to me.

Please note that I'm not asking how to name a variable, but how to do it in this very case. Examples and contexts where you used them will be much appreciated,

Thanks.

Upvotes: 2

Views: 712

Answers (8)

Ande Turner
Ande Turner

Reputation: 7212

Are these supposed to be constants ?

If you are doing it for legibility reasons exclusively why not create a method a la Dan's suggestion.

float complement(float n) { return (1.0 - n); }

Upvotes: 0

Hannes Landeholm
Hannes Landeholm

Reputation: 1629

There is no way to answer your question without knowing what "k" represents. Ironicly, the reason why that is not possible is the poor naming of the variable "k" in the first place, so that is what you should worry about instead. If you give "k" a more describing name, a good choise of naming for "k-1" should come naturally, like in the example of "will_win_lottery" and "will_not_win_lottery".

Upvotes: 1

Turnkey
Turnkey

Reputation: 9406

Your usage already seems descriptive enough, just go with it.

Upvotes: 0

Bill the Lizard
Bill the Lizard

Reputation: 405785

I would probably calculate that when I needed it. How much time do you think it saves to store it in a variable? Remember that premature optimization is the root of all evil.

Upvotes: 2

Dan Dyer
Dan Dyer

Reputation: 54485

I would call it the Complement.

Upvotes: 7

moo
moo

Reputation: 7789

Does it really matter? Use i; it's not any less descriptive than k. Things like this need to be documented/commented if you're that OCD about code descriptiveness.

Upvotes: -2

Vinko Vrsalovic
Vinko Vrsalovic

Reputation: 340321

In probability 1-k is the probability of X not occurring, given that k is the probability of X occurring.

So

float will_win_lottery = 0.00000000001;
float will_not_win_lottery = 1 - will_win_lottery;

Upvotes: 14

Scott James
Scott James

Reputation: 684

You should name your variables based on what it means in terms of the domain you are working on not the algorithm you used to produce it. Thus if k represented your house number k-1 may represent your next door neighbors house number. Name it accordingly.

Upvotes: 9

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