removing newline from eachline in file

[Chuck Dawit]

I'm reading a file line by line and trying to remove the newline at the
end of each line so that I can rebuild the url with the "www" and the
".net" at the beginning and end. Does anyone know how I can remove the
newline char at the end of each line? Also if the url doesn't work/exist
I don't want the script to crash I want to keep moving through the file
its reading.

begin
while (line = f.readline)
line = line =~ /(.*?)\n/
url = "www." + line + ".net"

open(url) { |page| page_content = page.read()
puts "link exists"
}
end
rescue
puts "link does not exist"

rescue EOFError
f.close
end

 

[7stud --]

I'm reading a file line by line and trying to remove the newline at the
end of each line so that I can rebuild the url with the "www" and the
".net" at the beginning and end. Does anyone know how I can remove the
newline char at the end of each line?

See String#chomp:

require "open-uri"

File.open("aaa.txt", "w") do |file|
file.print("hello\n", "world\n", "goodbye\n")
end

File.open("aaa.txt") do |file|
file.each do |line|
print line.chomp
end
puts
end

--output:--
helloworldgoodbye

 

[Tim Hunter]

I'm reading a file line by line and trying to remove the newline at the
end of each line so that I can rebuild the url with the "www" and the
".net" at the beginning and end. Does anyone know how I can remove the
newline char at the end of each line? Also if the url doesn't work/exist
I don't want the script to crash I want to keep moving through the file
its reading.

ri String#chomp
----------------------------------------------------------- String#chomp
str.chomp(separator=$/) => new_str
------------------------------------------------------------------------
Returns a new String with the given record separator removed from
the end of str (if present). If $/ has not been changed from the
default Ruby record separator, then chomp also removes carriage
return characters (that is it will remove \n, \r, and \r\n).

"hello".chomp #=> "hello"
"hello\n".chomp #=> "hello"
"hello\r\n".chomp #=> "hello"
"hello\n\r".chomp #=> "hello\n"
"hello\r".chomp #=> "hello"
"hello \n there".chomp #=> "hello \n there"
"hello".chomp("llo") #=> "he"

 

[7stud --]

Also if the url doesn't work/exist
I don't want the script to crash I want to keep moving through the file
its reading.

My isp redirects faulty urls to an error page, so all urls return a web
page. I think you're going to have to use Net::HTTP to look at the
headers of the response, and then take some action based on the header
value.

 

[7stud --]

Also if the url doesn't work/exist
I don't want the script to crash I want to keep moving through the file
its reading.

begin
while (line = f.readline)
line = line =~ /(.*?)\n/
url = "www." + line + ".net"

open(url) { |page| page_content = page.read()
puts "link exists"
}
end
rescue
puts "link does not exist"

rescue EOFError
f.close
end

If your program is currently crashing on bad urls, you just need to put
the begin/rescue around the open statement---not outside your loop.
Something like this(untested):

begin
while (line = f.readline)
line = line =~ /(.*?)\n/
url = "www." + line + ".net"

begin
open(url) { |page| page_content = page.read() }
puts "link exists"
rescue Exception
puts "in rescue"
#do nothing -- when you catch an exception the exception
goes away

puts "execution continues on its way"
end
end

 

[Tom Reilly]

Try changing the code to:
file_in = File.new("whatever")
file_in.each do |x|
url = x.chomp + ".net"

gud luck

 

[Peña, Botp]

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