If else

Dan Rathbun

Can the following be written in ruby? because it does not seem to work correctly

Try this:

if counter % 4.0 == 0.0
	machine = "#{a[counter]}"  	
elsif counter % 4.0 == 0.25
	x = a[counter].to_f
elsif counter % 4.0 == 0.5
	y = a[counter].to_f
elsif counter % 4.0 == 0.75
	rot = a[counter].to_i
end

Or this:

if counter / 4.0 == 0.0
	machine = "#{a[counter]}"  	
elsif counter / 4.0 == 0.25
	x = a[counter].to_f
elsif counter / 4.0 == 0.5
	y = a[counter].to_f
elsif counter / 4.0 == 0.75
	rot = a[counter].to_i
end

You need to use a Float as the divisor to get a Float result.

borg.stef

a = []
	counter = 0
	file = File.new("trial.txt", "r")
	while (line = file.gets)
		a[counter] = line

		if counter % 4 == 0     # lines 0 , 4, 8 etc
			machine = "#{a[counter]}" 
		elsif counter % 4 == 0.25      # lines 1, 5, 9 etc
			x = a[counter].to_f    
		elsif counter % 4 == 0.5    # lines 2, 6, 10 etc
      			y = a[counter].to_f    
		elsif counter % 4 == 0.75     # lines 3, 7, 11 etc
			rot = a[counter].to_i
end
end

Dan Rathbun

This should work:

a = []
counter = 0
file = File.new("trial.txt", "r")
while (line = file.gets)
	a[counter] = line

	if counter % 4 == 0.0     # lines 0 , 4, 8 etc
		machine = "#{a[counter]}" 
	elsif counter % 4 == 1.0      # lines 1, 5, 9 etc
		x = a[counter].to_f    
	elsif counter % 4 == 2.0    # lines 2, 6, 10 etc
      		y = a[counter].to_f    
	elsif counter % 4 == 3.0     # lines 3, 7, 11 etc
		rot = a[counter].to_i
	end
end

TIG

You haven't understood what I said several posts back
elsif counter % 4 == 0.25 # lines 1, 5, 9 etc
will never return true as it returns '1' NOT '0.25'... to test this simply type 1%4 or 5%4 in the Ruby Console and you'll get '1' NOT '0.25' !
Also note how 1/4 will return 0 because dividing an integer by an integer gives an integer [and 5/4 gives 1 !]... BUT 1/4.0 gives 0.25 as you have divided an integer by a float and you get a float.
SO your test is elsif counter % 4 == 1 # lines 1, 5, 9 etc

borg.stef

hmmm this worked now...but I didn't understand why you did 1% 4 = 1.0 etc?

Dan Rathbun

You may wish to use the 3rd line as:
file = IO.readlines("trial.txt")

.. then change the while loop to an array each iterator:
` file.each_with_index do |line,counter|

code

end`

Dan Rathbun

@borg.stef said:

hmmm this worked now...but I didn't understand why you did 1% 4 = 1.0 etc?

Because I did what TIG said, I tested it at the console, and saw it returned 1,2,3, ...

borg.stef

ok sorry TIG i saw your post now

Dan Rathbun

@dan rathbun said:

You may wish to use the 3rd line as:
file = IO.readlines("trial.txt")

.. then change the while loop to an array each iterator:
` file.each_with_index do |line,counter|

code

end`

If you do this, you do not need a = [], because the var file is the array ( IO.readlines returns an array of textlines.)

borg.stef

ok thanks both!!

Cleverbeans

From the looks of your code you're interested specifically in blocks of four lines, in which case you may gain some mileage out of the array.slice method by doing the following.


for i in 0..a.length/4 #there are i blocks of four lines
    machine,x,y,rot = a.slice(i*4,4)
    #more code
end