Do I lack understanding or arrays?


#1

I’m doing the pascal quiz on rubyquiz.com, but I’m finding that I’m
having trouble assigning a value to my array.

I’ve assigned it like this:

  pyramid_lvl[level][i] =\
      ( (pyramid[level-1][i-1]).to_i \
      + (pyramid[level-1][i]  ).to_i )

and like this:
num1 = pyramid[level-1][i-1].to_i
num2 = pyramid[level-1][i].to_i
ans = num1+num2
pyramid_lvl[level][i] = [ans]

Both give me this error message:
undefined method `[]=’ for 1:Fixnum (NoMethodError)

Am I getting this problem because I don’t understand how arrays work
and it’s simply a matter of operations, or am I having some serious
logical problem preventing correctness.


#2

removed_email_address@domain.invalid wrote:

  num1 = pyramid[level-1][i-1].to_i

From the error, I would venture to guess (pretty sure) that
pyramid_lvl[level] contains a number, not an array (as you seem to
think). I couldn’t say more without reading more code.

Dan


#3

Hi –

On Mon, 28 May 2007, removed_email_address@domain.invalid wrote:

 num1 = pyramid[level-1][i-1].to_i
 num2 = pyramid[level-1][i].to_i
 ans = num1+num2
 pyramid_lvl[level][i] = [ans]

Both give me this error message:
undefined method `[]=’ for 1:Fixnum (NoMethodError)

Am I getting this problem because I don’t understand how arrays work
and it’s simply a matter of operations, or am I having some serious
logical problem preventing correctness.

It’s just what the error says: you’re trying to call the method []= on
the object 1 :slight_smile: That means that pyramid_lvl[level] must be 1. So
when you do:

pyramid_lvl[level][i] = whatever

it’s like you’re doing:

1[i] = whatever

That’s equivalent to a method call:

1[]=(i, whatever)

and 1 has no method called []= so you get an error.

I can’t tell you where in your code you assigned 1 to
pyramid_lvl[level], but that appears to be what’s happening.

David


#4

I tested this:

pyramid_lvl[level][i] is 0
pyramid[level-1][i] is 1
pyramid[level-1][i-1] is 1

Turns out that pyramid[level-1][i] was actually nil… which makes
this a logical error, not a syntax error.

So I pretty much just waisted your time, but so long and thanks for
all the fish.


#5

was actually nil
typo. I meant 0