Zoe P. wrote:
output =
30.times do [rand(citylist.length)]
First of all Integer#times returns self, so 30.times will return 30
which
means that the value of output will be 30.
Second of all rand(foo) returns a number between 0 (inclusive) and foo
(exclusive). [rand(foo)] will simply return an array containing that
number.
So the value of [rand(citylist.length)] may be [5] or [4], but it will
never
be a city name. Also as you don’t do anything with the value the whole
thing
won’t have any effect on the result of the program.
%Q(W
ebsite #{rand(citylist.length)} | )
end
This will create links like “…website1.html”, “website5.html” etc. It
won’t
contain city names. If you want a random city name you have to do:
citylist[rand(citylist.length)] which might evaluate to citylist[5] for
example which will evaluate to a city name.
Also as with the previous array you don’t do anything with the string
you
created here (the string will be the return value of the block, but the
times
method doesn’t care about the block’s return value, so it will be
discarded).
The two instances of the
city inside the block should be the same, but I’m not sure how to do
that.
As I explained, there aren’t any cities in the block, just numbers. And
those
are not the same (except if rand returns the same number twice by
coincidence)
If you want to use one random city multiple times do:
city = citylist[rand(citylist.length)]
And then do stuff with city. If you want to remove that city from the
list (so
you won’t pick it again when you take another random city), you can use:
city = citylist.delete_at(rand(citylist.length))
So now city might be “miami” and the citylist will no longer contain
miami.
Doesn’t rand make it a random city each time it’s interpreted or
since it’s in a block, would it be the same each time the block
repeats…?
It makes a random number each time it’s called.
Here’s some code that should work:
output = Array.new(30) do
city = citylist.delete_at(rand(citylist.length))
%Q(Website
#{city} | )
end
File.open(filename, ‘w’) do |f|
f.write output
end
(Array.new(x) will execute the block x times and store the result of the
block
in the array after each execution)
Or if you don’t need the temporary array that creates:
File.open(filename, “w”) do |f|
30.times do
city = citylist.delete_at(rand(citylist.length))
f.puts %Q(Website
#{city} | )
end
end
Of course in both solutions citylist will be modified in the process
(i.e. the
30 cities will be removed). If that’s a problem you should use Robert’s
solution (which has the upside that it doesn’t affect citylist and the
downside that it sorts the entire list, which might be undesirable if
the
list is considerably larger than 30 entries).
HTH,
Sebastian