Array indexing

Ruby
1

hey …

I want to make sure that I understand the subtle difference in the
syntax.

my_array[0,3]

and

my_array[0…2]

both will return the same array elements - correct?

the first says: “start at index0 & gimme 3”
the latter say: “start at index0 and goto index2”

If the data requirements start at >index0, then there is no offset
between the “gimme” and the 'goto".

Am I getting it?

2

Duke N. wrote in post #994657:

hey …

I want to make sure that I understand the subtle difference in the
syntax.

my_array[0,3]

and

my_array[0…2]

both will return the same array elements - correct?

If someone had a gun to your head and told you that you had 30 seconds
to provide an answer to that question, what would you do?

the first says: “start at index0 & gimme 3”
the latter say: “start at index0 and goto index2”

Where is the ruby documentation for the Array class located?

If the data requirements start at >index0, then there is no offset
between the “gimme” and the 'goto".

Am I getting it?

Huh?

3

On Sun, 24 Apr 2011, Josh C. wrote:

On Sat, Apr 23, 2011 at 11:22 AM, Duke N. [email protected] wrote:

hey …

I want to make sure that I understand the subtle difference in the
syntax.

[snip]

IDK, but a quick study of behaviour should make it very obvious:

[snip the good stuff]

Thanks for all that!

However, I think that I summarized it in my original post, exactly as
you are showing it above. My definition of “gimme” and “goto” may not
be as clear as what I had hoped it would be. No matter! I’ll check my
understanding of the issue against what you’ve provided above. Much
obliged!

4

On Sat, Apr 23, 2011 at 11:22 AM, Duke N. [email protected]
wrote:

Duke

IDK, but a quick study of behaviour should make it very obvious:

numbers = *0…10 # => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

numbers[0,3] # => [0, 1, 2]
numbers[1,3] # => [1, 2, 3]
numbers[2,3] # => [2, 3, 4]
numbers[3,3] # => [3, 4, 5]

numbers[0,4] # => [0, 1, 2, 3]
numbers[1,4] # => [1, 2, 3, 4]
numbers[2,4] # => [2, 3, 4, 5]
numbers[3,4] # => [3, 4, 5, 6]

numbers[0…5] # => [0, 1, 2, 3, 4, 5]
numbers[1…5] # => [1, 2, 3, 4, 5]
numbers[2…5] # => [2, 3, 4, 5]
numbers[3…5] # => [3, 4, 5]

numbers[3…7] # => [3, 4, 5, 6, 7]
numbers[4…7] # => [4, 5, 6, 7]
numbers[5…7] # => [5, 6, 7]
numbers[6…7] # => [6, 7]
numbers[7…7] # => [7]

If you’re using TextMate, you can update the comments with
command+control+shift+e. Otherwise, you might try entering each line
into
irb, and it will update for you the correct value. Or you could write a
program to cycle through inputs and print the values, something like:

numbers = *0…10

(0…3).each do |start|
result = numbers[start,3]
puts “numbers[#{start},3] # => #{result.inspect}”
end

On Sat, Apr 23, 2011 at 12:02 PM, 7stud – [email protected]
wrote:

If someone had a gun to your head and told you that you had 30 seconds
to provide an answer to that question, what would you do?

Ruby is serious business.