Passing a function with arguments to another function with arguments that is a loop


#1

Hi, I am a noobie. I just want to know what is the standard or most
effective way of doing this

I have two functions

def display_price(grocery,batch)
grocery_price = grocery.send(batch).price
if grocery_price
number_to_currency(grocery_price)
else
“NA”
end
end

def loop(func,matrix)

matrix.each { |matrix| display_price(@grocery,matrix) }

end

the “func argument” in the loop function is suppose to be
display_price but how do i put it in if the “batch” is the thing that
I want to be looped through?


#2

You can create a pointer to your display_price method with a Proc
object, e.g.:

this_func = Proc.new {|groc, bat| display_price(groc, bat)}

loop(this_func, batch)

Your loop method invokes the actual function with the .call method,
e.g.:

def loop(func, matrix)
# Note that .each will almost certainly not yield the matrix object
itself.
matrix.each { |matrix_item| func.call(@grocery, matrix) }
end

No clue if that will work for your actual application–trying to figure
out what you might be doing is making my head hurt. :wink: This feels like
it’s well outside of noob-land. If you back up & tell us more about
your underlying goals, we may be able to give advice for staying w/more
straightforward processing.

HTH,

-Roy


#3

In the end I did it this way.

def loop_td(func,matrix,grocery,name)
holder = ["

" + name + “”]
for x in matrix
holder << ("" + send(func,grocery,x) + “”)
end
return holder

end

display_price is the func I want to insert

def display_price(grocery,batch)
grocery_price = grocery.send(batch).price
if grocery_price
number_to_currency(grocery_price)
else
“NA”
end
end

The underlying goal was to make a function where I could automatically
generate a table row that used the same function in each

for with
the
same array.

-yl(thanks for answering btw)