# String scanning woes :(
**URL:** https://rubytalk.org/t/string-scanning-woes/44265
**Category:** ruby-talk
**Created:** [5 February 2008 00:54 UTC](https://rubytalk.org/t/string-scanning-woes/44265 "2008-02-05T00:54:58Z")
**Posts on this page:** 11
**Page:** 1
### Author:  [@Lovell](https://rubytalk.org/u/Lovell)
#### Post date: [5 February 2008 00:54 UTC](https://rubytalk.org/t/string-scanning-woes/44265/1 "2008-02-05T00:54:58Z")
Hello all,
I am trying to get a file into an array using .scan and I can't seem
to get anything to work properly.
I am reading in a file of email addresses (1 per line) and it all
seems to come in as 1 long string some how. I am trying to use scan
to break it up into an array of emails so that I can do some uniq
checks and validation with other arrays. But I just don't seem to get
it right.
My code right now is as follows:
emails = File.open("/users/lem/desktop/test/
POCs\_DNB.txt","r").readlines.map! {|x| x.chomp} # Read in the list
of emails
email.scan(/\S+/) # To mach on spaces (I assume). I thought I would
be matching on new lines
puts email # To verify
When I did an inspect on the email variable The address appeared as
such
"foo1@bar.edu\foo2@bar.com\foo3@bar.gov......"
This is my absolute first time working with .scan and regular
expressions so I have a little bit of a learning curve with this one.
Any help is greatly appreciated.
---
### Author:  [@Brandon\_Jones](https://rubytalk.org/u/Brandon_Jones)
#### Post date: [5 February 2008 01:25 UTC](https://rubytalk.org/t/string-scanning-woes/44265/2 "2008-02-05T01:25:03Z")
You could try this to make it a bit easier:
File.open("/users/lem/desktop/test/POCs\_DNB.txt", "r").each\_line do |
line\>
line.chomp!
# now you have a single line (sans newline) from your file
end
# no need to close the file either 馃槂
> **路路路**
>
> On Feb 4, 7:50 pm, Vell \ wrote:
>
> > Hello all,
> >
> > I am trying to get a file into an array using .scan and I can't seem
> > to get anything to work properly.
> >
> > I am reading in a file of email addresses (1 per line) and it all
> > seems to come in as 1 long string some how. I am trying to use scan
> > to break it up into an array of emails so that I can do some uniq
> > checks and validation with other arrays. But I just don't seem to get
> > it right.
> >
> > My code right now is as follows:
> >
> > emails = File.open("/users/lem/desktop/test/
> > POCs\_DNB.txt","r").readlines.map! {|x| x.chomp} # Read in the list
> > of emails
> > email.scan(/\S+/) # To mach on spaces (I assume). I thought I would
> > be matching on new lines
> > puts email # To verify
> >
> > When I did an inspect on the email variable The address appeared as
> > such
> >
> > "f...@bar.edu\f...@bar.com\f...@bar.gov......"
> >
> > This is my absolute first time working with .scan and regular
> > expressions so I have a little bit of a learning curve with this one.
> >
> > Any help is greatly appreciated.
---
### Author:  [@botp1](https://rubytalk.org/u/botp1)
#### Post date: [5 February 2008 01:46 UTC](https://rubytalk.org/t/string-scanning-woes/44265/3 "2008-02-05T01:46:32Z")
to avoid doubt, try slowly.
this is a first mod/run of your posted code, eg,
botp@pc4all:~$ cat test.txt
foo1@bar.edu
foo2@bar.com
foo3@bar.gov
botp@pc4all:~$ cat test.rb
p File.readlines("test.txt").map{|x| x.chomp}
botp@pc4all:~$ ruby test.rb
["foo1@bar.edu", "foo2@bar.com", "foo3@bar.gov"]
that is just one way. there are many ways if using ruby.
kind regards -botp
> **路路路**
>
> On Feb 5, 2008 8:54 AM, Vell \ wrote:
>
> > I am trying to get a file into an array using .scan and I can't seem
> > to get anything to work properly.
---
### Author:  [@7stud](https://rubytalk.org/u/7stud)
#### Post date: [5 February 2008 02:07 UTC](https://rubytalk.org/t/string-scanning-woes/44265/4 "2008-02-05T02:07:36Z")
Lovell Mcilwain wrote:
> Hello all,
>
> I am trying to get a file into an array using .scan and I can't seem
> to get anything to work properly.
>
> I am reading in a file of email addresses (1 per line) and it all
> seems to come in as 1 long string some how. I am trying to use scan
> to break it up into an array of emails so that I can do some uniq
> checks and validation with other arrays. But I just don't seem to get
> it right.
>
> My code right now is as follows:
>
> emails = File.open("/users/lem/desktop/test/
> POCs\_DNB.txt","r").readlines.map! {|x| x.chomp}
>
> email.scan(/\S+/)
scan() returns an array. You don't assign the array to any variable, so
it is discarded.
> When I did an inspect on the email variable The address appeared as
> such
>
> "foo1@bar.edu\foo2@bar.com\foo3@bar.gov......"
Nowhere in the code you posted does a variable named email exist.
> This is my absolute first time working with .scan and regular
> expressions so I have a little bit of a learning curve with this one.
>
> Any help is greatly appreciated.
If you expect to get relevant help, you should post a short example
progrram that demonstrates your problem, i.e. an example program that
anyone can run and get the same results you do.
> **路路路**
>
> --
> Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C).
---
### Author:  [@W\_James](https://rubytalk.org/u/W_James)
#### Post date: [5 February 2008 11:44 UTC](https://rubytalk.org/t/string-scanning-woes/44265/5 "2008-02-05T11:44:56Z")
First you say "emails"; then you say "email".
This is not code that will run.
Didn't you copy and paste? Don't tell us that you
retyped the code because you were eager for the chance
to introduce errors.
p IO.readlines( "data" ).map{|x| x.strip }
p IO.read( "data" ).split
p IO.read( "data" ).scan(/\S+/)
> **路路路**
>
> On Feb 4, 6:50 pm, Vell \ wrote:
>
> > emails = File.open("/users/lem/desktop/test/
> > POCs\_DNB.txt","r").readlines.map! {|x| x.chomp}
> > email.scan(/\S+/)
---
### Author:  [@Lovell](https://rubytalk.org/u/Lovell)
#### Post date: [5 February 2008 05:39 UTC](https://rubytalk.org/t/string-scanning-woes/44265/6 "2008-02-05T05:39:57Z")
> Lovell Mcilwain wrote:
> \> Hello all,
>
> \> I am trying to get a file into an array using .scan and I can't seem
> \> to get anything to work properly.
>
> \> I am reading in a file of email addresses (1 per line) and it all
> \> seems to come in as 1 long string some how. I am trying to use scan
> \> to break it up into an array of emails so that I can do some uniq
> \> checks and validation with other arrays. But I just don't seem to get
> \> it right.
>
> \> My code right now is as follows:
>
> \> emails = File.open("/users/lem/desktop/test/
> \> POCs\_DNB.txt","r").readlines.map! {|x| x.chomp}
>
> \> email.scan(/\S+/)
>
> scan() returns an array. You don't assign the array to any variable, so
> it is discarded.
>
> \> When I did an inspect on the email variable The address appeared as
> \> such
>
> \> "f...@bar.edu\f...@bar.com\f...@bar.gov......"
>
> Nowhere in the code you posted does a variable named email exist.
Very first line of my code is what I thought to be a variable...
> \> This is my absolute first time working with .scan and regular
> \> expressions so I have a little bit of a learning curve with this one.
>
> \> Any help is greatly appreciated.
>
> If you expect to get relevant help, you should post a short example
> progrram that demonstrates your problem, i.e. an example program that
> anyone can run and get the same results you do.
The code I posted is exactly what I ran aside for giving you
hundrededs of lines of email. The example is exactly what I ran to
get the results I posted.
> **路路路**
>
> On Feb 4, 9:07 pm, 7stud -- \ wrote:
>
> > --
> > Posted viahttp://www.ruby-forum.com/.
---
### Author:  [@Lovell](https://rubytalk.org/u/Lovell)
#### Post date: [5 February 2008 16:39 UTC](https://rubytalk.org/t/string-scanning-woes/44265/7 "2008-02-05T16:39:57Z")
> \> emails = File.open("/users/lem/desktop/test/
> \> POCs\_DNB.txt","r").readlines.map! {|x| x.chomp}
> \> email.scan(/\S+/)
>
> First you say "emails"; then you say "email".
> This is not code that will run.
>
> Didn't you copy and paste? Don't tell us that you
> retyped the code because you were eager for the chance
> to introduce errors.
I'm a beginner, lighten up James.
> **路路路**
>
> On Feb 5, 6:40 am, William James \ wrote:
>
> > On Feb 4, 6:50 pm, Vell \ wrote:
>
> > p IO.readlines( "data" ).map{|x| x.strip }
> > p IO.read( "data" ).split
> > p IO.read( "data" ).scan(/\S+/)
---
### Author:  [@7stud](https://rubytalk.org/u/7stud)
#### Post date: [5 February 2008 06:45 UTC](https://rubytalk.org/t/string-scanning-woes/44265/8 "2008-02-05T06:45:18Z")
Lovell Mcilwain wrote:
> The code I posted is exactly what I ran aside for giving you
> hundrededs of lines of email. The example is exactly what I ran to
> get the results I posted.
emails = File.open("data.txt").readlines.map! {|x| x.chomp}
email.scan(/\S+/)
--output:--
r1test.rb:2: undefined local variable or method `email' for main:Object
(NameError)
> **路路路**
>
> --
> Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C).
---
### Author:  [@Robert\_K1](https://rubytalk.org/u/Robert_K1)
#### Post date: [5 February 2008 09:52 UTC](https://rubytalk.org/t/string-scanning-woes/44265/9 "2008-02-05T09:52:53Z")
Though shalt use the block form of File.open to ensure proper cleanup!
Apart from that there is another way:
require 'set'
addresses = Set.new
File.foreach "data.txt" do |line|
line.chomp!
line.downcase!
puts "Duplicate: #{line}" unless addresses.add? line
end
Cheers
robert
> **路路路**
>
> 2008/2/5, 7stud -- \:
>
> > Lovell Mcilwain wrote:
> > \>
> > \> The code I posted is exactly what I ran aside for giving you
> > \> hundrededs of lines of email. The example is exactly what I ran to
> > \> get the results I posted.
> > \>
> >
> > emails = File.open("data.txt").readlines.map! {|x| x.chomp}
> > email.scan(/\S+/)
>
> --
> use.inject do |as, often| as.you\_can - without end
---
### Author:  [@W\_James](https://rubytalk.org/u/W_James)
#### Post date: [5 February 2008 12:24 UTC](https://rubytalk.org/t/string-scanning-woes/44265/10 "2008-02-05T12:24:55Z")
h = {}
File.foreach("data"){|e|
e = e.strip.upcase
puts "Duplicate: #{ e }" if h.include? e
h[e] = true
}
> **路路路**
>
> On Feb 5, 3:52 am, Robert Klemme \ wrote:
>
> > require 'set'
> > addresses = Set.new
> >
> > File.foreach "data.txt" do |line|
> > line.chomp!
> > line.downcase!
> >
> > puts "Duplicate: #{line}" unless addresses.add? line
> > end
---
### Author:  [@Lovell](https://rubytalk.org/u/Lovell)
#### Post date: [5 February 2008 16:39 UTC](https://rubytalk.org/t/string-scanning-woes/44265/11 "2008-02-05T16:39:57Z")
Thanks guys for all the helpful hints.
> **路路路**
>
> On Feb 5, 7:20 am, William James \ wrote:
>
> > On Feb 5, 3:52 am, Robert Klemme \ wrote:
> >
> > \> require 'set'
> > \> addresses = Set.new
> >
> > \> File.foreach "data.txt" do |line|
> > \> line.chomp!
> > \> line.downcase!
> >
> > \> puts "Duplicate: #{line}" unless addresses.add? line
> > \> end
> >
> > h = {}
> > File.foreach("data"){|e|
> > e = e.strip.upcase
> > puts "Duplicate: #{ e }" if h.include? e
> > h[e] = true
> >
> > }