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comp.lang.ruby

Re: Cleaner way to do this?

Harry Ohlsen

11/5/2004 1:24:00 AM

> -----Original Message-----
> From: Wayne Vucenic [mailto:nightphotos@gmail.com]
> Sent: Friday, 5 November 2004 12:12
> To: ruby-talk ML
> Subject: Re: Cleaner way to do this?
>
> How about
>
> [1, 2, 3, 4, 5].each_with_index do |x, i|
> if i == 0
> print x
> else
> print ", ",x
> end
> end

That's what I initially suggested :-).

However, he felt it was a bit crazy to do the test every time, given the
large size of the array.

H.


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6 Answers

Zach Dennis

11/5/2004 3:01:00 AM

0

Harry Ohlsen wrote:

>> -----Original Message-----
>> From: Wayne Vucenic [mailto:nightphotos@gmail.com]
>> Sent: Friday, 5 November 2004 12:12
>> To: ruby-talk ML
>> Subject: Re: Cleaner way to do this?
>>
>> How about
>>
>> [1, 2, 3, 4, 5].each_with_index do |x, i|
>> if i == 0
>> print x
>> else
>> print ", ",x
>> end
>> end
>>
>>
>
>That's what I initially suggested :-).
>
>However, he felt it was a bit crazy to do the test every time, given the
>large size of the array.
>
>H.
>

If your friend knows the processing he wants to do on the first element,
why not just keep it simple...


arr = [1,2,3,4,5]
process = proc{ |e| print e }.call( arr[0] )
arr[1...arr.length].each do |e|
print ", #{e}"
end

Zach

Zach Dennis

11/5/2004 4:22:00 AM

0

Zach Dennis wrote:

>
> If your friend knows the processing he wants to do on the first
> element, why not just keep it simple...
>
>
> arr = [1,2,3,4,5]
> process = proc{ |e| print e }.call( arr[0] )
> arr[1...arr.length].each do |e|
> print ", #{e}"
> end
>
This is also faster, then doing a comparison in each iteration :

RESULTS:

---------- Capture Output ----------
"C:\ruby\bin\ruby.exe" -d harry_ohlsen.rb
WRITING 1
Took:
19.297000169754
seconds
WRITING 2
Took: 11.7650001049042 seconds
Terminated with exit code 0

--------CODE-----------
require 'time'

arr = []
2000000.times do |i|
arr << "abcdefghijklmnopqrstuvwxyz"
end

f = File.new( "temp.txt" , "w+" )
t = Time.new
arr.each_with_index do |x,i|
if i==0
f.print x
else
f.print ', ',x
end
end
f.close
puts "WRITING 1"
puts "Took: ", (Time.new.to_f - t.to_f).to_s, " seconds"

f = File.new( "temp.txt2" , "w+" )
t = Time.new
process = proc { |e| f.print e }.call( arr[0] )
arr[1...arr.length].each do |e|
f.print ', ',e
end
f.close
puts "WRITING 2"
print "Took: ", (Time.new.to_f- t.to_f).to_s, " seconds"

benny

11/5/2004 1:33:00 PM

0

Harry Ohlsen wrote:

>> -----Original Message-----
>> From: Wayne Vucenic [mailto:nightphotos@gmail.com]
>> Sent: Friday, 5 November 2004 12:12
>> To: ruby-talk ML
>> Subject: Re: Cleaner way to do this?
>>
>> How about
>>
>> [1, 2, 3, 4, 5].each_with_index do |x, i|
>> if i == 0
>> print x
>> else
>> print ", ",x
>> end
>> end
>
> That's what I initially suggested :-).
>
> However, he felt it was a bit crazy to do the test every time, given the
> large size of the array.
>

how about this?

arr = [1, 2, 3, 4, 5]
first = arr.shift
print arr.inject(first) { | c, i | "#{c.to_s}, #{i.to_s}" }

benny

benny

11/5/2004 1:57:00 PM

0

benny wrote:

> Harry Ohlsen wrote:
>
>>> -----Original Message-----
>>> From: Wayne Vucenic [mailto:nightphotos@gmail.com]
>>> Sent: Friday, 5 November 2004 12:12
>>> To: ruby-talk ML
>>> Subject: Re: Cleaner way to do this?
>>>
>>> How about
>>>
>>> [1, 2, 3, 4, 5].each_with_index do |x, i|
>>> if i == 0
>>> print x
>>> else
>>> print ", ",x
>>> end
>>> end
>>
>> That's what I initially suggested :-).
>>
>> However, he felt it was a bit crazy to do the test every time, given the
>> large size of the array.
>>
>
> how about this?
>
> arr = [1, 2, 3, 4, 5]
> first = arr.shift
> print arr.inject(first) { | c, i | "#{c.to_s}, #{i.to_s}" }
>
> benny

or even

print [1, 2, 3, 4, 5].join(' ,')

benny

benny

11/5/2004 2:04:00 PM

0

benny wrote:

>
> arr = [1, 2, 3, 4, 5]
> first = arr.shift
> print arr.inject(first) { | c, i | "#{c.to_s}, #{i.to_s}" }
>
> benny

now I saw the initial post :)
sorry for the noise

benny

dblack

11/5/2004 2:07:00 PM

0