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comp.lang.ruby

Array#insert implementation

Zuzzurro

1/25/2005 3:12:00 PM

Hi,

I need an insert method for the Array class, the insert method let you
do something like this:

a = ['a', 'b', 'd']
a.insert!(2, 'C')

a => ['a', 'b', 'C', 'd']


I've implemented it this way:

class Array
def insert(v, i)
i = 0 if i < 0
a = Array.new
a += self[0..i-1] if i > 0
a << v
tail = self[i..-1] if i < self.length
a += tail unless tail.nil?
return a
end

def insert!(v, i)
new_self = insert(v, i)
clear
concat new_self
end
end


Is there a better way of doing this?
4 Answers

Robert Klemme

1/25/2005 3:33:00 PM

0


"Zuzzurro" <celhoquilabrioche@zuzzurro.it> schrieb im Newsbeitrag
news:1106665910.3709.5.camel@localhost.localdomain...
> Hi,
>
> I need an insert method for the Array class, the insert method let you
> do something like this:
>
> a = ['a', 'b', 'd']
> a.insert!(2, 'C')
>
> a => ['a', 'b', 'C', 'd']
>
>
> I've implemented it this way:
>
> class Array
> def insert(v, i)
> i = 0 if i < 0
> a = Array.new
> a += self[0..i-1] if i > 0
> a << v
> tail = self[i..-1] if i < self.length
> a += tail unless tail.nil?
> return a
> end
>
> def insert!(v, i)
> new_self = insert(v, i)
> clear
> concat new_self
> end
> end
>
>
> Is there a better way of doing this?

>> a = %w{a b c d}
=> ["a", "b", "c", "d"]
>> a[2,0]=%w{1 2 3}
=> ["1", "2", "3"]
>> a
=> ["a", "b", "1", "2", "3", "c", "d"]

Kind regards

robert

Zuzzurro

1/25/2005 3:49:00 PM

0

Il giorno mar, 25-01-2005 alle 16:32 +0100, Robert Klemme ha scritto:
> "Zuzzurro" <celhoquilabrioche@zuzzurro.it> schrieb im Newsbeitrag
> news:1106665910.3709.5.camel@localhost.localdomain...
> > Hi,
> >
> > I need an insert method for the Array class, the insert method let you
> > do something like this:
> >
> > a = ['a', 'b', 'd']
> > a.insert!(2, 'C')
> >
> > a => ['a', 'b', 'C', 'd']
> >
> >
> > I've implemented it this way:
> >
> > class Array
> > def insert(v, i)
> > i = 0 if i < 0
> > a = Array.new
> > a += self[0..i-1] if i > 0
> > a << v
> > tail = self[i..-1] if i < self.length
> > a += tail unless tail.nil?
> > return a
> > end
> >
> > def insert!(v, i)
> > new_self = insert(v, i)
> > clear
> > concat new_self
> > end
> > end
> >
> >
> > Is there a better way of doing this?
>
> >> a = %w{a b c d}
> => ["a", "b", "c", "d"]
> >> a[2,0]=%w{1 2 3}
> => ["1", "2", "3"]
> >> a
> => ["a", "b", "1", "2", "3", "c", "d"]
>
> Kind regards
>
> robert
>

thank you.

Florian Gross

1/25/2005 9:23:00 PM

0

Zuzzurro wrote:

> class Array
> def insert(v, i)
> [...]
> Is there a better way of doing this?

Sure, just use Array#insert:

irb(main):043:0> ary = [1, 2, 3]; ary.insert(1, 5); ary
=> [1, 5, 2, 3]

Zuzzurro

1/26/2005 8:24:00 AM

0

Il giorno mar, 25-01-2005 alle 22:23 +0100, Florian Gross ha scritto:
> Zuzzurro wrote:
>
> > class Array
> > def insert(v, i)
> > [...]
> > Is there a better way of doing this?
>
> Sure, just use Array#insert:
>
> irb(main):043:0> ary = [1, 2, 3]; ary.insert(1, 5); ary
> => [1, 5, 2, 3]

nice to see they added #insert in the 1.8 version, I'm still using 1.6
tough, so I did the following:

class Array
def insert(i, v)
self[i,0] = v
end
end

as suggested by Robert Klemme.

Regards,
Paolo.