Extract a range start/end?

ruby-talk
1

if i have a list of dates in an array such as:

4/2/07
4/3/07
4/4/07
4/5/07
4/6/07
4/7/07
4/8/07
ect.

how would i..based on option parse..pull a starting point and end point
of to extract that data range.

IE:

opts = OptionParser.new do |opts|
opts.on("-s", "--startdate", "What start date to use." do |i|
   #code to determine to use the starting date
end

# the same would apply to an --enddate

any ideas?

i was thinking i could possibly create a new range depending on what the
user input was by doing

require 'date'
results = []

(Date.new(2007,4,1)..Date.new(2007,4,8)).each {|r| res << r}
but then how would i match that against the original dates for the data?

feel free to give me any thoughts.

-Thanks

···

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2

I think that range operates on numbers, and method "to_i" casts class to
number, so your class should have specific method "to_i".

Yours,
Killavus.

···

2007/9/2, Michael Linfield <globyy3000@hotmail.com>:

if i have a list of dates in an array such as:

4/2/07
4/3/07
4/4/07
4/5/07
4/6/07
4/7/07
4/8/07
ect.

how would i..based on option parse..pull a starting point and end point
of to extract that data range.

IE:

opts = OptionParser.new do |opts|
opts.on("-s", "--startdate", "What start date to use." do |i|
   #code to determine to use the starting date
end

# the same would apply to an --enddate

any ideas?

i was thinking i could possibly create a new range depending on what the
user input was by doing

require 'date'
results =

(Date.new(2007,4,1)..Date.new(2007,4,8)).each {|r| res << r}
but then how would i match that against the original dates for the data?

feel free to give me any thoughts.

-Thanks
--
Posted via http://www.ruby-forum.com/\.

3

Hi Michael,

opts = OptionParser.new do |opts|
opts.on("-s", "--startdate", "What start date to use." do |i|
   #code to determine to use the starting date

# see Parsedate#parsedate at
http://www.ruby-doc.org/stdlib/libdoc/parsedate/rdoc/classes/ParseDate.html#M001494

@startdate = Parsedate.parsedate i

end

i was thinking i could possibly create a new range depending on what the
user input was by doing

require 'date'
results =

# delete this

(Date.new(2007,4,1)..Date.new(2007,4,8)).each {|r| res << r}

result = (@startdate..@enddate).to_a

but then how would i match that against the original dates for the data?

match = original & result

Oyasumi
Florian

4

From rdoc:
Ranges can be constructed using objects of any type, as long as
     the objects can be compared using their <=> operator and they
     support the succ method to return the next object in sequence.

In practice, that usually means 'Anything that has Enumerable as an ancestor'

···

On 9/2/07, Marcin Grzywaczewski <killavus@gmail.com> wrote:

2007/9/2, Michael Linfield <globyy3000@hotmail.com>:
>
> if i have a list of dates in an array such as:
>
> 4/2/07
> 4/3/07
> 4/4/07
> 4/5/07
> 4/6/07
> 4/7/07
> 4/8/07
> ect.
>
> how would i..based on option parse..pull a starting point and end point
> of to extract that data range.
>
> IE:
>
> opts = OptionParser.new do |opts|
> opts.on("-s", "--startdate", "What start date to use." do |i|
> #code to determine to use the starting date
> end
>
> # the same would apply to an --enddate
>
> any ideas?
>
> i was thinking i could possibly create a new range depending on what the
> user input was by doing
>
> require 'date'
> results =
>
> (Date.new(2007,4,1)..Date.new(2007,4,8)).each {|r| res << r}
> but then how would i match that against the original dates for the data?
>
> feel free to give me any thoughts.
>
> -Thanks
> --
> Posted via http://www.ruby-forum.com/\.

I think that range operates on numbers, and method "to_i" casts class to
number, so your class should have specific method "to_i".

5

little flaw:

Florian Aßmann schrieb:

Hi Michael,

opts = OptionParser.new do |opts|
opts.on("-s", "--startdate", "What start date to use." do |i|
   #code to determine to use the starting date

# see Parsedate#parsedate at

···

#
http://www.ruby-doc.org/stdlib/libdoc/parsedate/rdoc/classes/ParseDate.html#M001494

- @startdate = Parsedate.parsedate i
+ @startdate = Date.new(*ParseDate.parsedate(i)[0,3])

end

6

Oh, my bad. Sorry :)...

Yours,
Killavus.

···

2007/9/2, Wilson Bilkovich <wilsonb@gmail.com>:

On 9/2/07, Marcin Grzywaczewski <killavus@gmail.com> wrote:
> 2007/9/2, Michael Linfield <globyy3000@hotmail.com>:
> >
> > if i have a list of dates in an array such as:
> >
> > 4/2/07
> > 4/3/07
> > 4/4/07
> > 4/5/07
> > 4/6/07
> > 4/7/07
> > 4/8/07
> > ect.
> >
> > how would i..based on option parse..pull a starting point and end
point
> > of to extract that data range.
> >
> > IE:
> >
> > opts = OptionParser.new do |opts|
> > opts.on("-s", "--startdate", "What start date to use." do |i|
> > #code to determine to use the starting date
> > end
> >
> > # the same would apply to an --enddate
> >
> > any ideas?
> >
> > i was thinking i could possibly create a new range depending on what
the
> > user input was by doing
> >
> > require 'date'
> > results =
> >
> > (Date.new(2007,4,1)..Date.new(2007,4,8)).each {|r| res << r}
> > but then how would i match that against the original dates for the
data?
> >
> > feel free to give me any thoughts.
> >
> > -Thanks
> > --
> > Posted via http://www.ruby-forum.com/\.
>
>
> I think that range operates on numbers, and method "to_i" casts class to
> number, so your class should have specific method "to_i".
>

From rdoc:
Ranges can be constructed using objects of any type, as long as
     the objects can be compared using their <=> operator and they
     support the succ method to return the next object in sequence.

In practice, that usually means 'Anything that has Enumerable as an
ancestor'

7

Florian Aßmann wrote:

little flaw:

Florian Aßmann schrieb:

Hi Michael,

opts = OptionParser.new do |opts|
opts.on("-s", "--startdate", "What start date to use." do |i|
   #code to determine to use the starting date

# see Parsedate#parsedate at
#
http://www.ruby-doc.org/stdlib/libdoc/parsedate/rdoc/classes/ParseDate.html#M001494

- @startdate = Parsedate.parsedate i
+ @startdate = Date.new(*ParseDate.parsedate(i)[0,3])

if you dont mind my asking,

@startdate = Date.new(*ParseDate.parsedate(i)[0,3])

can someone explain how that line of code works, i'd rather understand
it so that i actually know what it does when i insert it into my code

Thanks!

···

--
Posted via http://www.ruby-forum.com/\.

8

Wilson Bilkovich wrote:

From rdoc:

Ranges can be constructed using objects of any type, as long as
     the objects can be compared using their <=> operator and they
     support the succ method to return the next object in sequence.

In practice, that usually means 'Anything that has Enumerable as an ancestor'

You meant Comparable, right? There's no connection between Enumerable and #<=> or #succ.

···

--
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407

9

Ok, I though you were familiar with some of the RubyDoc ressources...

Here I go:
ParseDate and Date are part of the Ruby StdLib, therefore in order to use this
you need to:
require 'parsedate'
require 'date'

Next thing I think you expect something like '1/20/2007' as dateformat:
./my_app.rb --startdate 1/20/2007

This 'll be parsed by:
ParseDate.parsedate('1/20/2007') # => [2007,1,20,nil,nil,nil]

To generate an instance of Date out of this we simply call Date.new, but wait,
Date.new only accepts 3 args (maybe 4, though).

Therefore I invoke the slice-method ([]) on the freshly baken array:
# I assume i = '1/20/2007'
ParseDate.parsedate(i)[0, 3] # => [2007,1,20]

To split the array into seperate arguments when I invoke Date.new I need the
*-Operator: a_method(*[1,2,3]) is like a_method(1,2,3)

Date.new(*ParseDate.parsedate(i)[0, 3]) # => <Date... >

Tada, you got your Date now...

Further reading:
Ruby Stdlib: Date and ParseDate
Ruby Classes and Libraries: Array.slice

Regards
Florian

10

You are correct. Not enough sleep this weekend.

···

On 9/2/07, Joel VanderWerf <vjoel@path.berkeley.edu> wrote:

Wilson Bilkovich wrote:
>>From rdoc:
> Ranges can be constructed using objects of any type, as long as
> the objects can be compared using their <=> operator and they
> support the succ method to return the next object in sequence.
>
> In practice, that usually means 'Anything that has Enumerable as an ancestor'

You meant Comparable, right? There's no connection between Enumerable
and #<=> or #succ.

11

but then how would i match that against the original dates for the data?
match = original & result

now as far as matching that date to grep'd data should i use a string
comparison or is there a better way?

···

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