Nested loops

Rails
1

Hi,
I have loops that loop through params values from a form and retrieve
records from the database and then plot a graph.

BUT:
If the user selects a check box in the form the loop is 3 nested loops
instead of 5.

ALSO:
There is another checkbox that causes 5 loops (same as first case) but
does an extra calculation on the records in the inner loop.

My point is these 3 cases are similar: how should I deal with them?

At the moment the loops all occur in the controller - should I move them
to a model - a model for each graph type?

Or should I have one set of loops and do some clever conditional flow to
get all three cases out of it?

Any ideas on the best practice when doing loops?

Chris.

2

Why on earth do you need 5 nested loops? What are you trying to do?

3

Mick S. wrote:

Why on earth do you need 5 nested loops? What are you trying to do?

Well, the query to make up the graph requires 5 different parameters -
it is to graph measurements made on a machine:
there are 10 machines - so the user selects one (or multiple)
there are 8 different measurement types
there are 2 types of machine output
there are 3 types of something else
they must select the date range
and a check box whether they want the results as % of a reference value
or not.

I then, for each machine, loop through what is required and get the
results from the database on the inner loop.
I then loop through it all to send results to gnuplot.

It starts to become a head ache.

Questions from my first post still stand.

Chris.

4

You might be able to dry up your code using some code that I knocked up
to iterate over a number of arrays using nested looping:

http://www.ruby-forum.com/topic/95539

5

Mick S. wrote:

You might be able to dry up your code using some code that I knocked up
to iterate over a number of arrays using nested looping:

Nested looping - Rails - Ruby-Forum

Great Mick, that’s a slick bit of code - could be just what I need.

6

Chris F. wrote:

Mick S. wrote:

You might be able to dry up your code using some code that I knocked up
to iterate over a number of arrays using nested looping:

Nested looping - Rails - Ruby-Forum

Great Mick, that’s a slick bit of code - could be just what I need.

Darn, I have to do some processing between loops - i.e. not just on the
inner loop - don’t think I can use it:-(

C