If statement - how do I reduce amount of code. (loop? array?) Javascript

Question

I have 10 variables. q1 through q10

my script is as follows:

if (q1 == '1') { q1 = 'Yes'; 
} else if (q1 == '2') { q1 = 'No';
} else { q1 = 'Did Not Answer'; }

I already typed this out for all 10. I am not sure if I can insert another variable into this variable.

I'm trying to do something like this:

var ex = '1';
while (ex < 11) { 
if (q[ex] == '1') { q[ex] = 'Yes'; ex++;
} else if (q[ex] == '0') { q[ex] = 'No'; ex++;
} else { q[ex] = 'Did Not Answer'; ex++ }

Basically I want to eliminate 4 lines of code x 10 variables.

[ex] is a variable inside the variable (to represent q1, determine q1 = Yes, No, or Did Not Answer, then add 1 to q[ex] which would now be q2....

I understand that the [] may not be correct, I just don't know how to explain this in a way that is understandable.

Thank you.

• varela: what about using switch - case statement? Map with results (array) would be the best as for me, it would be understandable
• Felix Kling: possible duplicate of Alternative to a million IF statements
• Pointy: Maybe instead of 10 variables you just need one - an array.

Answer 1

This wouldn't limit it down all the way but you could create a function

translate = function(v)
{
 if (v === '1') { 
 v = 'Yes'; 
 } else if (v === '2') { 
 v = 'No';
 } else { 
 v = 'Did Not Answer'; 
 }
 return var
}

Then call translate(q1) etc for each variable. That would move it to ~16 lines rather than 40 and avoid repeating code.

You also could reform your variables as an array of variables and loop through quickly like that, but I don't know where they are all being defined and how that would work for you. EDIT: Bergi has a good example of this. If you can reform your variables like that, that is the best way to go.

• Nicholas Decker: Of course this makes more sense to me :) The variables are coming from the post of a form.
• Nicholas Decker: I'm fairly new to javascript and I was trying to get the other answer working, but couldn't figure it out. I will work on this later this afternoon.
• Ben McCormick: Ok no problem. Bergi's solution is definitely the most space efficient way to do this. Mine is probably a bit more readable. So whichever makes the most sense for you.
• Ben McCormick: Great good to hear. feel free to accept the answer if it was helpful
• Bergi: @ben336: Please rename your variable. "var" is a reserved word, I even doubt this function would ever work.

Answer 2

See my answer on Alternative to a million IF statements.

The while-loop is of course a good thing, you should really use an array q instead of single variables qN. You might also use a for-loop.

If you want to eleminate the if-statements, you might use an object with indexes (in here an array, which is naturally indexed from "0" to "n-1", does the same job):

var q = ["0", "1", 1, 0, 2, ...];
for (var i=0; i<q.length; i++)
 q[i] = ["No", "Yes"][q[i]] || "Did Not Answer";
// result for q:
["No", "Yes", "Yes", "No", "Did Not Answer", ...]

• Nicholas Decker: After reading the original (alternative to a mill.....) I wasn't sure of the answer, however this explanation is a little more tailored to what I am doing. Thank you. I believe with the explanation I can adapt this to the 4 or 5 places that I will need these in my script. I appreciate the edit. I was a little lost by the first part.
• Bergi: Yes, I needed to adapt that answer a bit. You also were asking on using arrays instead of 10 variables. The [...] is a literal expression for arrays, you might fill your array dynamically of course.
• Nicholas Decker: for the var q =etc how come some are "0" and others are just 0
• Bergi: It just means: It will work both for strings, numbers and everything else that will be converted to "0" or "1" (the indizes of the array) when beeing converted to a property name.
• Nicholas Decker: I used the other answer because this was a little over my head, however I will learn a little bit more and would believe I will accept your answer.