Array#insert implementation

[Zuzzurro]

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?

 

[Robert Klemme]

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]

Il giorno mar, 25-01-2005 alle 16:32 +0100, Robert Klemme ha scritto:

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]

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]

Il giorno mar, 25-01-2005 alle 22:23 +0100, Florian Gross ha scritto:

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.