Array Manupulation

Rails
1

Can anyone help me on the following?

I have the following 2 arrays, how do i get c as a result of a and b.
The elements should be in the specified order.

a = ["(modulable_type=?) AND (parent_id=?) AND
(status=?)",“Task”,“2”,“20”]
b = ["(tasks.due_date=?)", “2009-08-22”]

c = ["(modulable_type=?) AND (parent_id=?) AND (status=?) AND
(tasks.due_date=?)",“Task”,“2”,“20”,“2009-08-22”]

Thanks and Regards,
Pratik

2

Answer:

a[0] = a[0] + " AND " + b[0]

  b.length.times do |i|
    if i!=0
a << b[i]

end
end

3

2009/8/23 tispratik [email protected]:

c = [“(modulable_type=?) AND (parent_id=?) AND (status=?) AND
(tasks.due_date=?)”,“Task”,“2”,“20”,“2009-08-22”]

I have encountered exactly this problem and realised that, though this
is solvable, it is better (if possible) to build the arrays
differently in the first place. I realise this may not be possible
for you but if you change the original conditions building so that it
builds two arrays of the form
conditions = [“(modulable_type=?)”,“(parent_id=?)”]
and
values = [“Task”,“2”] and so on, so just adding each condition and
value as they arise, then the required result is
c = [conditions.join(" AND ")] + values

No doubt there are even better ways, and it may not match your needs
anyway, but for me it worked well as I was working through a number of
options building the conditions as I went.

Colin

and b similarly
Then c = (a+b).collect(

4

On Aug 23, 1:15 am, tispratik [email protected] wrote:

(tasks.due_date=?)",“Task”,“2”,“20”,“2009-08-22”]

Thanks and Regards,
Pratik

Instead of doing funky array manipulation to build your model’s SQL
find conditions, are you absolutely sure you shouldn’t just be using
scopes instead?

5

Doing things like this, it may be easier to use the named placeholders
version - so your example will look like:

a = ["(modulable_type=:modulable_type) AND (parent_id=:parent_id) AND
(status=:status)",{:modulable_type => “Task”, :parent_id =>
“2”, :status => “20”}]
b = ["(tasks.due_date=:due_date)", {:due_date => “2009-08-22”}]

Then c is as simple as:

c = ["#{a[0]} AND #{b[0]}", a[1].merge(b[1])]

Note: this will fail in creative ways if you have parameters in a and
b that are supposed to have different values but have the same name,
so don’t do that. :slight_smile:

–Matt J.

6

pharrington wrote:

On Aug 23, 1:15�am, tispratik [email protected] wrote:

(tasks.due_date=?)",“Task”,“2”,“20”,“2009-08-22”]

Thanks and Regards,
Pratik

Instead of doing funky array manipulation to build your model’s SQL
find conditions, are you absolutely sure you shouldn’t just be using
scopes instead?

Or if not scopes, plain old conditions hashes. If you’re trying to use
this as a :conditions parameter to find, remember that :conditions will
also take a hash:

[“(modulable_type=?) AND (parent_id=?) AND (status=?) AND
(tasks.due_date=?)”,“Task”,“2”,“20”,“2009-08-22”]
{:modulable_type => ‘Task’, :parent_id => 2 … }
Best,

Marnen Laibow-Koser
http://www.marnen.org
[email protected]