Asp Forum - for loop - comp.lang.ruby

dare ruby

11/21/2007 3:59:00 AM

Consider the following for loop in 'C' or 'c++' or 'java'

for (i=namespaceEnd - 1; i >= 0; i--)

Please help me with code to do the same functionality in ruby
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11 Answers

Carl

11/21/2007 4:17:00 AM

Martin Durai <martin@angleritech.com> writes:

> Consider the following for loop in 'C' or 'c++' or 'java'
>
> for (i=namespaceEnd - 1; i >= 0; i--)
>
> Please help me with code to do the same functionality in ruby
> --
> Posted via http://www.ruby-....

How about this:

(namespace_end - 1).downto(0) { |x| puts x }

Hope that helps,
Carl.

dare ruby

11/21/2007 4:40:00 AM

Thank you carl, iam very new to this language

sorry carl could you help with this code fully

for( int i = namespaceEnd -1; i >= 0; i--) {
if( prefix.equals( namespacePrefix[ i ] ) ) {
return namespaceUri[ i ];
}

thank you in advance

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Todd Burch

11/21/2007 5:25:00 AM

Martin Durai wrote:
> Thank you carl, iam very new to this language
>
> sorry carl could you help with this code fully
>
> for( int i = namespaceEnd -1; i >= 0; i--) {
> if( prefix.equals( namespacePrefix[ i ] ) ) {
> return namespaceUri[ i ];
> }
>
>
> thank you in advance

(namespace_end - 1).downto(0) { |x|
return namespaceUri[x] if prefix==namespacePrefix[x] }

Todd
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Carl

11/21/2007 5:44:00 AM

Martin Durai <martin@angleritech.com> writes:

> Thank you carl, iam very new to this language
>
> sorry carl could you help with this code fully
>
> for( int i = namespaceEnd -1; i >= 0; i--) {
> if( prefix.equals( namespacePrefix[ i ] ) ) {
> return namespaceUri[ i ];
> }
>
>
> thank you in advance
>

I suspect you're looking for the element in the namespaceUri
array which is at the position determined by looking up the
position of 'prefix' in the namespacePrefix array (how very
unsettling). Assuming namespaceEnd is actually the count of
elements in the namespacePrefix array, would this work?

your_value = (i = namespace_prefix.index(prefix)) ?
namespace_uri[i] :
nil

Where 'your_value' will now contain the namespace_uri value,
or nil if it was not found in namespace_prefix

If i've misunderstood your question, post back with the values
of prefix, namespacePrefix, namespaceUri and namespaceEnd, and
what you expect to get out of it and I'll see if I can't help.

Carl

11/21/2007 5:47:00 AM

Todd Burch <promos@burchwoodusa.com> writes:

> Martin Durai wrote:
>> Thank you carl, iam very new to this language
>>
>> sorry carl could you help with this code fully
>>
>> for( int i = namespaceEnd -1; i >= 0; i--) {
>> if( prefix.equals( namespacePrefix[ i ] ) ) {
>> return namespaceUri[ i ];
>> }
>>
>>
>> thank you in advance
>
> (namespace_end - 1).downto(0) { |x|
> return namespaceUri[x] if prefix==namespacePrefix[x] }
>
> Todd

I'm getting a 'LocalJumpError: unexpected return' error when
I try to return from within a downto block, is this supported
in your version?

Carl.

Lloyd Linklater

11/21/2007 5:50:00 AM

Martin Durai wrote:
> Consider the following for loop in 'C' or 'c++' or 'java'
>
> for (i=namespaceEnd - 1; i >= 0; i--)
>
> Please help me with code to do the same functionality in ruby

ruby does not really have a for loop as such but there are various ways
to get the job done. You saw the upto approach. Here is another:

namespaceEnd.times do
# your code in here
end

now, this works for 0..namespace - 1 automatically. If you need to run
in reverse, can use the downto or a calculation.

namespaceEnd.times do |my_var|
some_array[namespaceEnd - my_var] = some_val
end

but that is clunky. If you are iterating through an array you can use
the each loop:

my_arr = ["aaa", "bbb", "ccc", "ddd"]
my_arr.each_with_index {|str, idx| puts "#{idx}. #{str}"}

=>
0. aaa
1. bbb
2. ccc
3. ddd

If you want only the values, use my_arr.each
If you want only the index position, use my_arr.each_index

HTH
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Paul McMahon

11/21/2007 6:01:00 AM

On Wed, 21 Nov 2007 13:39:58 +0900, Martin Durai <martin@angleritech.com=
> =

wrote:

> Thank you carl, iam very new to this language
>
> sorry carl could you help with this code fully
>
> for( int i =3D namespaceEnd -1; i >=3D 0; i--) {
> if( prefix.equals( namespacePrefix[ i ] ) ) {
> return namespaceUri[ i ];
> }
>
>
> thank you in advance
>

You might consider using an array of namespace objects instead of parall=
el =

arrays

class Namespace
attr_reader :prefix, :uri
def initialize(prefix, uri)
@prefix =3D prefix
@uri =3D uri
end
end

namespaces =3D [ Namespace.new("prefix", "uri"), ...]

then your code becomes something like:

matching_namespace =3D namespaces.find {|namespace| namespace.prefix =3D=
=3D =

prefix)
return matching_namespace ? matching_namespace.uri : nil

Carl

11/21/2007 6:10:00 AM

Paul McMahon <pm@ubit.com> writes:
>
> You might consider using an array of namespace objects instead of parallel
> arrays
>
> class Namespace
> attr_reader :prefix, :uri
> def initialize(prefix, uri)
> @prefix = prefix
> @uri = uri
> end
> end
>
> namespaces = [ Namespace.new("prefix", "uri"), ...]
>
> then your code becomes something like:
>
> matching_namespace = namespaces.find {|namespace| namespace.prefix ==
> prefix)
> return matching_namespace ? matching_namespace.uri : nil

Good point.
I suspect in this case a plain old Hash might do wonders to simplify
the problem...

Carl.

dare ruby

11/21/2007 6:52:00 AM

Sorry the code is running well in my system. I didnt got any error. I
have checked the code with my applications.

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Robert Klemme

11/21/2007 7:02:00 AM

On 21.11.2007 04:59, Martin Durai wrote:
> Consider the following for loop in 'C' or 'c++' or 'java'
>
> for (i=namespaceEnd - 1; i >= 0; i--)
>
> Please help me with code to do the same functionality in ruby

Did you actually read a tutorial or book about the language? If not,
it's probably easier to do that vs. trying to cover all these basic
questions via newsgroup...

Cheers

robert

comp.lang.ruby

for loop

dare ruby

Carl

dare ruby

Todd Burch

Carl

Carl

Lloyd Linklater

Paul McMahon

Carl

dare ruby

Robert Klemme

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