problem with reading file

[Li Chen]

Hi folks,

I read a file in the following format,extract the second column only,
and push them into an array. My problem is that Ruby reads them as
strings(based on array.inspect) but not as numbers so it is impossible
for me to do the calculation. Any comments?

Thanks,

Li

###filen name: array.text


A 1 B
A 2 B
A 3 B
A 4 B
A 5 B
A 6 B

...

###script

equire 'enumerator'

array=Array.new

File.open('array.text').each{|line| array<<line.split(/\t/)[1]}

#puts array.inspect
array.each_slice(3){|slice|
average=(slice[0]+slice[1]+slice[2])/(3.0)
puts average
}

###output from screen

C:/Ruby/self/file6.rb:8: undefined method `/' for "123":String
(NoMethodError)
from
c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
`each_slice'
from C:/Ruby/self/file6.rb:7:in `each'
from C:/Ruby/self/file6.rb:7:in `each_slice'
from C:/Ruby/self/file6.rb:7

 

[Wilson Bilkovich]

Hi folks,

I read a file in the following format,extract the second column only,
and push them into an array. My problem is that Ruby reads them as
strings(based on array.inspect) but not as numbers so it is impossible
for me to do the calculation. Any comments?

Thanks,

Li

###filen name: array.text


A 1 B
A 2 B
A 3 B
A 4 B
A 5 B
A 6 B

...

###script

equire 'enumerator'

array=Array.new

File.open('array.text').each{|line| array<<line.split(/\t/)[1]}

#puts array.inspect
array.each_slice(3){|slice|
average=(slice[0]+slice[1]+slice[2])/(3.0)
puts average
}

###output from screen

C:/Ruby/self/file6.rb:8: undefined method `/' for "123":String
(NoMethodError)
from
c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
`each_slice'
from C:/Ruby/self/file6.rb:7:in `each'
from C:/Ruby/self/file6.rb:7:in `each_slice'
from C:/Ruby/self/file6.rb:7

You need to tell Ruby to coerce the strings into integers.

array = []

File.open('array.text') do |file|
file.each_line do |line|
array << line.split[1].to_i
end
end

array.each_slice(3) do |triplet|
average = (slice[0]+slice[1]+slice[2])/3.0
puts average
end

 

[Li Chen]

You need to tell Ruby to coerce the strings into integers.

array = []

File.open('array.text') do |file|
file.each_line do |line|
array << line.split[1].to_i
end
end

array.each_slice(3) do |triplet|
average = (slice[0]+slice[1]+slice[2])/3.0
puts average
end

Thank you very much,

Li

 

[Robert Klemme]

Hi folks,

I read a file in the following format,extract the second column only,
and push them into an array. My problem is that Ruby reads them as
strings(based on array.inspect) but not as numbers so it is impossible
for me to do the calculation. Any comments?

Thanks,

Li

###filen name: array.text


A 1 B
A 2 B
A 3 B
A 4 B
A 5 B
A 6 B

..

###script

equire 'enumerator'

array=Array.new

File.open('array.text').each{|line| array<<line.split(/\t/)[1]}

#puts array.inspect
array.each_slice(3){|slice|
average=(slice[0]+slice[1]+slice[2])/(3.0)
puts average
}

###output from screen

C:/Ruby/self/file6.rb:8: undefined method `/' for "123":String
(NoMethodError)
from
c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
`each_slice'
from C:/Ruby/self/file6.rb:7:in `each'
from C:/Ruby/self/file6.rb:7:in `each_slice'
from C:/Ruby/self/file6.rb:7

This can be done by an awk style 1liner

18:12:44 [Temp]: cat data
A 1 B
A 2 B
A 3 B
A 4 B
A 5 B
A 6 B
18:13:18 [Temp]: ruby -aF\\t -n -r enumerator -e 'BEGIN{$a=[]};
$a<<$F[1].to_i; END{ $a.each_slice(3){|sl| p
sl.inject(0){|a,b|a+b}/3.0}}' data
2.0
5.0
18:13:34 [Temp]:

Kind regards

robert