Noob devision question

Ruby
1

I’m trying to make a percentage progress bar for an XMMS web interface,
I want to take the total track time and the elapsed time and then make
a length for the bar from the percentage completed.

something like:

totalbarsize = 180
timeelapsed = 10
totaltime = 30

percomplete = 0.0
barlength = 0.0

percomplete = timeelapsed / totaltime
barlength = totalbarsize*percomplete

puts barlength

Now that should give me a barlength of 60 pixels but it gives 0
instead. Anyone know what I’m doing wrong?

Thanks!

(I’ll forget that I need barlength as an integer rather than a float
for now :-P)

2

jamiethehutt wrote:

percomplete = 0.0
Thanks!

(I’ll forget that I need barlength as an integer rather than a float
for now :-P)

timeelapsed and totaltime are Integers. So when you divide them, it does
integer division:

irb(main):001:0> 10/30
=> 0
irb(main):002:0> 10.0 / 30.0
=> 0.333333333333333

try

percomplete = timeelapsed.to_f / totaltime

or

percomplete = timeelapsed / totaltime.to_f

or

percomplete = timeelapsed.to_f / totaltime.to_f

or

totaltime = 30.0
timeelapsed = 10.0

You get the idea :slight_smile: Floats for floating point division.

-Justin

3

Division of 2 integers results in an integer. So, try setting
timeelapsed to 10.0 instead of 10.

Tim

4

jamiethehutt wrote:
…

puts barlength
You need Floats all the way down.
The division of Fixnum values ( timeelapsed / totaltime)
produces a Fixnum value, which is 0 as 0.333 gets truncated

put a .0 after all the non-Float values to force them to be Float

5

“jamiethehutt” [email protected] writes:

percomplete = 0.0
barlength = 0.0

percomplete = timeelapsed / totaltime

This is an integer-division, and since totaltime is always bigger than
timeelapsed (in theory :wink: it is always 0.
You could try defining totaltime as 30.0 initially or write it as
percomplete = timeelapsed.to_f / totaltime
or something.

barlength = totalbarsize*percomplete

puts barlength

Now that should give me a barlength of 60 pixels but it gives 0
instead. Anyone know what I’m doing wrong?

Thanks!

Tom

6

jamiethehutt wrote:

percomplete = 0.0
Thanks!

(I’ll forget that I need barlength as an integer rather than a float
for now :-P)

10/30
=> 0

10*100/30
=> 33

7

ChrisH wrote:

barlength = totalbarsize*percomplete

puts barlength

You need Floats all the way down.
The division of Fixnum values ( timeelapsed / totaltime)
produces a Fixnum value, which is 0 as 0.333 gets truncated

put a .0 after all the non-Float values to force them to be Float

Fogot to say, to get an Integer (or Fixnum id Ruby parlance) just call
to_i on the Float value to covert by truncating the value.

cheers

8

Use quo. For example:

percomplete = timeelapsed.quo(totaltime) => 0.333333333333333

Regards, Morton