Shortening Multiple IF Conditions for the Same Variable

Question

(first stackoverflow post) This is a javaScript question, but I think the logic applies anywhere

I've wondered for a long time about using an if statement to compare multiple values against the same variable without needing to type out the variable every time; specifically, in regards to "greater than" and "less than".

The specific example I'm trying to solve is:

var middle = 5;
if(middle < 10 && middle > 0) {
    //some stuff
}

I'm looking for something like:

var middle = 5;
if(middle (< 10 && > 0)) {
    //the same stuff
}

I have checked is-there-a-way-to-shorten-the-condition-if-it-always-compares-to-the-same-thing and if-statements-matching-multiple-values and if-statement-multiple-conditions-same-statement. I could not derive a simple answer to my specific question from those.

A final note: I do not want to make a new "multiple if" function that accepts arguments and then compares them for the variable. I am looking for a "built-in" way to do this.

Thanks, -Charles

how many range binding comparisons do you actually need? Usually only two are necessary. — zzzzBov, Mar 27 '14 at 21:10
There is no such way. You can write a wrapper function that returns a boolean value, but you'll still have to write the logic out in that. — Etheryte, Mar 27 '14 at 21:11
Huh... After some (failed) attempts, I've determined that it's not as easy as I thought to make the wrapper function without using eval(). Any tips on this side question? — goodguy5, Mar 28 '14 at 15:47

score 4 · Accepted Answer · answered Mar 27 '14 at 21:54

4

Some languages like Python and Coffeescript (which compiles to JS!) have chained comparisons:

if (0 < middle < 10)

However, Javascript does not have these. Just as you already do, you will need to reference the variable twice:

if (0 < middle && middle < 10)

answered Mar 27 '14 at 21:54

Bergi

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Thanks, Bergi. That was the information I was looking for. – goodguy5 Mar 28 '14 at 15:37

score 1 · Answer 2 · answered Mar 27 '14 at 21:13

1

I don't believe it's possible, for a logical operator you need both sides of the operator to evaluate to true or false.

If you are missing a side the statement can't be evaluated.

answered Mar 27 '14 at 21:13

MrHaze

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score 0 · Answer 3 · edited Mar 27 '14 at 21:55

0

I am looking for a "built-in" way to do this.

Javascript doesn' t support this feature. In fact, most languages don't and Python is the only famous example I can think of right now that does that (you can write 0 < middle < 10 there).

In Javascript, the best you can do is use a shorter variable name

if(0 <= x && x < 10)

Or abstract common tests into a function

if(between(0, x, 10))

edited Mar 27 '14 at 21:55

Bergi

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answered Mar 27 '14 at 21:12

hugomg

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That's 4 more characters, not even counting white space! :D – Gary Hayes Mar 27 '14 at 21:14
It's only four more characters because 'x' is very short. If your variable were 10 characters, then it would start to be clearly shorter. – goodguy5 Mar 28 '14 at 15:39

score 0 · Answer 4 · answered Mar 27 '14 at 21:33

0

Right, don't do this, but just for the sake of it :

if (Math.min(10, Math.max(0, middle)) == middle) {
   // middle is between 0 and 10
}

answered Mar 27 '14 at 21:33

Theo.T

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score 0 · Answer 5 · answered Oct 20 '21 at 04:33

0

If anyone is doing this in python for multiple values you can try this

exclude = ['10','0','20','30','12','14']
if i not in exclude:
   print(i)

answered Oct 20 '21 at 04:33

Ankit Arora

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10

As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Oct 20 '21 at 04:35

Shortening Multiple IF Conditions for the Same Variable

5 Answers5

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