Hi,
i am new to ruby and i am wondering how many more ways (and what ways)
there are to do this:
seperated_words = “hi, you, guys”
words_array = seperated_words.split(",")
for i in 0 … words_array.length
words_array[i] = words_array[i].strip
end
i suppose there’s a one-liner that you write before you can think “ruby”
doesn’t it ???
thx,
chris
“hi, you, guys”.split(",").map! { |x| x.strip }
Chris M. a écrit :
i suppose there’s a one-liner that you write before you can think “ruby”
doesn’t it ???thx,
chris
Hi,
this is my version :
“hi, you, guys”.split(’,’).map { |word| word.strip }
=> [“hi”, “you”, “guys”]
Split recieves a regexp as an argument. So you can be as tricky as you
like
with it.
“hi, you, guys”.split( %r{\s*,\s*} )
=>[ “hi”,“you”,“guys”]
good timing to you first two guys;)
thx very much. got some new ruby cells working in my brain.
i tried same thing as “.map” with “array.each” before, but this does
only apply on a copy i suppose…
and of course the regexp way is … groovy!
use map! instead
Your version has no side-effect on the array, so it’s not exactly the
same as the original … 
On 11/9/06, Robert D. [email protected] wrote:
“he, nice, guys”.split(‘,’).map!{|x| x.strip}
why would you use map! ?
try to put the above expression into a context
e.g.
x = …Hint: using map! on unreferenced objects is quite useless.
Robert, I don’t really understand what you mean. My understanding is
that
these do different things. Can I walk through this in pseudo pseudo
code to
increase my understanding;)
split the string into an unref’ed array
take the unreffed array and strip each element in place, creating a new
string at each element in the original array
Total Arrays created 2
How does this not differ from
“he, nice, guys”.split(‘,’).map{|x| x.strip}
Where, my understanding would be
split the string into an unref’ed array
take the unref’ed array, and create a new array from the result of each
element stripped.
ie. a new string object for each element put into a new array
Total Arrays created 3
What about
x= “he, nice”.split(“,”)
x.map!{|x|x.strip}
split the string and assign it to an array
modify each element in place and strip the result. (creating a new
string
for each element)
try
x.map!{|x|x.strip!}
would you like to use this?
Nasty… Turns the first element (with no whitespace) into nil
Have I understood the difference/similarities here or have I missed the
ball?
you are absolutely correct, my mind is rotting from weeks of sitting
at my desk twiddling my thumbs with no work to do.
On 11/9/06, spooq [email protected] wrote:
use map! instead
nope,
try to understand the difference between split(regexp), map and map!
than decide for yourself
Look at this for example
“he, nice, guys”.split(‘,’).map!{|x| x.strip}
why would you use map! ?
try to put the above expression into a context
e.g.
x = …
Hint: using map! on unreferenced objects is quite useless.
What about
x= “he, nice”.split(“,”)
x.map!{|x|x.strip}
try
x.map!{|x|x.strip!}
would you like to use this?
If you want to walk do not learn to drive 
Cheers
Robert
On 11/9/06, Chris M. [email protected] wrote:
Posted via http://www.ruby-forum.com/.
–
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore all progress
depends on the unreasonable man.
On 11/9/06, Daniel N [email protected] wrote:
than decide for yourself
Look at this for example“he, nice, guys”.split(‘,’).map!{|x| x.strip}
“he, nice, guys”.split(“,”) ===> tmp1 ← [“he”, " nice", " guys" ]
tmp1.map!{|x| x.strip} ===> tmp2 ← [“he”, “nice”, “guys”] ** and
modifies the object referenced by tmp1 in place ***
why would you use map! ?
try to put the above expression into a context
e.g.
x = …Hint: using map! on unreferenced objects is quite useless.
The idea was to work on the differences between xxx and xxx!
Robert, I don’t really understand what you mean. My understanding is
that
these do different things. Can I walk through this in pseudo pseudo code
to
increase my understanding;)
Excellent idea.
split the string into an unref’ed array
take the unreffed array and strip each element in place, creating a new
string at each element in the original array
which will get lost, the only thing you use is the result of the
expression, s
Total Arrays created 2
I have no idea
How does this not differ from
“he, nice, guys”.split(‘,’).map{|x| x.strip}
“he, nice, guys”.split(“,”) ===> tmp1 ← [“he”, " nice", " guys" ]
tmp1.map!{|x| x.strip} ===> tmp2 ← [“he”, “nice”, “guys”] ***
without modifiying tmp1 inplace ***
Performance is not an issue, but I guess it is important to understand
why
one would apply map! (ignoring the existance of map would not be a good
reason)
Where, my understanding would be
split the string into an unref’ed array
take the unref’ed array, and create a new array from the result of each
element stripped.
ie. a new string object for each element put into a new array
exactly (this is done too above, it would not work else)
Total Arrays created 3
Again I have no idea
What about
would you like to use this?
Nasty… Turns the first element (with no whitespace) into nil
No for the same reason as above why use x.strip! modifiying x when x
will
be discarded immediately? I thaught this would be the ice breaker
example
Have I understood the difference/similarities here or have I missed the
ball?
Baseball?
BTW Sometimes I get caught in the urge to explain, forgetting that
experience has shown to me that I am quite a bad teacher
Cheers
Robert
–
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore all progress
depends on the unreasonable man.
On 2006-11-09, Chris M. [email protected] wrote:
i suppose there’s a one-liner that you write before you can think “ruby”
doesn’t it ???
Functionally slightly different, but:
words_array = separated_words.split(/, /)
Hi –
On Thu, 9 Nov 2006, Chris M. wrote:
Hi,
i am new to ruby and i am wondering how many more ways (and what ways)
there are to do this:seperated_words = “hi, you, guys”
words_array = seperated_words.split(",")
for i in 0 … words_array.length
words_array[i] = words_array[i].strip
end
Here’s one way:
separated_words.scan(/[^\s,]+/)
And another:
require ‘csv’
CSV.parse_line(separated.words.delete(’ '))
David
On Thu, 9 Nov 2006, Chris M. wrote:
i suppose there’s a one-liner that you write before you can think “ruby”
doesn’t it ???
My favourite cheat is…
$ irb
irb(main):001:0> %w{hi you guys}
=> [“hi”, “you”, “guys”]
irb(main):002:0>
Not quite as much as a cheat as you think…
People keep creating small ugly special purpose once off data
languages like xml, csv, yaml,…
Unless there is a pressing need to store in language neutral format,
for pity sake don’t.
Just store your data as plain old ruby.
Simpler and more expressive.
John C. Phone : (64)(3) 358 6639
Tait Electronics Fax : (64)(3) 359 4632
PO Box 1645 Christchurch Email : [email protected]
New Zealand
Kero [email protected] wrote:
i suppose there’s a one-liner that you write before you can think
“ruby” doesn’t it ???Functionally slightly different, but:
words_array = separated_words.split(/, /)
And yet another one
irb(main):002:0> “hi, you, guys”.split /\s*,\s*/
=> [“hi”, “you”, “guys”]
irb(main):003:0> “hi, you, guys”.scan /\w+/
=> [“hi”, “you”, “guys”]
Cheers
robert
Chris M. wrote:
i suppose there’s a one-liner that you write before you can think “ruby”
Chris,
Assuming that the string convention stays a comma plus a single space
between words why not add the single space in to the split string and
write
seperated_words = “hi, you, guys”
word_array = seperated_words.split(", ")
CParticle
Charged Particle wrote:
Assuming that the string convention stays a comma plus a single space
between words why not add the single space in to the split string and
write
i forgot to mention that the comma seperated list comes from a text_area
and may not include a whitespace after each “,”
thank you all for your posts, i learned quite a lot about the many roads
to rome that ruby (and regex) provides
p.s: maybe i should start another competiton 
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