Nil object problem

Rails
1

This is a repost as I had zero replies to my first email. This problem
is
driving me mad but it has to be a simple solution that I just can;t see.

Can someone please tell me what the difference is between the following
bits
of code …

<% @swimming_class.lessons.each do |lesson| %>
<% lesson.lesson_register.attendees.each do |att| %>
<%= att.enrollee_id %>


<% end %>
<% end %>

<% @swimming_class.lessons.each do |lesson| %>
<% lesson.lesson_register.attendees[0].enrollee_id %>
<% end %>

Thsnk you

–
The sun comes up and we start again

2

On Aug 31, 7:57 pm, Anthony G. [email protected] wrote:

<br />

<% lesson.lesson_register.attendees[0].enrollee_id %>
<% end %>

if a lesson register has no attendees the second snippet will try to
access it anyway whereas the first won’t

Fred

3

Frederick,

Thanks for getting back but you’re missing the point, they’re working
on
the same data.

The .each block iterates over the data correctly but the same data
throws
the nil object error when I index the item.

That’s the problem.

-Ants

2009/8/31 Frederick C. [email protected]

You have a nil object when you didn’t expect it!

Fred

Thsnk you

–
The sun comes up and we start again

–
100% naturally selected. 0% designed.

4

On Aug 31, 8:16 pm, Anthony G. [email protected] wrote:

Frederick,

Thanks for getting back but you’re missing the point, they’re working on
the same data.

I realise.

The .each block iterates over the data correctly but the same data throws
the nil object error when I index the item.

If the array is empty then each will be a no-op, unlike accessing [0].
Sounds like somewhere there is an item with no attendees.

Fred

5

Yes, you’re right!

I won’t go into where the mistake was but although the problem was in
the
code I submitted, the error (just my way of thinking, was in another
part of
the code)

So what you said got me thinking and I addressed another part of the
code
and found the error.

Merci!!

2009/8/31 Frederick C. [email protected]

-Ants

This is a repost as I had zero replies to my first email. This
<% @swimming_class.lessons.each do |lesson| %>

Thsnk you

–
The sun comes up and we start again

–
100% naturally selected. 0% designed.

–
100% naturally selected. 0% designed.