Array range values assignment

[Ruby Fan]

a = ["A","A","A","A","A", "A","A","A","A","A"]
a[3...7] = "B"

QUESTION:
after code executes a = ["A", "A", "A", "B", "A", "A", "A"]
what should I do to make a = ["A", "A", "A", "B", "B", "B", "B", "A",
"A", "A"]

 

[Gunther Diemant]

[Note: parts of this message were removed to make it a legal post.]

Just
a[3...7] = ['B','B','B','B'].

Works at least in 1.9.2.

 

[Ruby Fan]

I understand that

But I need some universal way to change values of arrays with 10+
elements

 

[Ruby Fan]

Found way:

b = []
a[3...7].size.times do b.push("B") end
a[3...7] = b

is there anything simplier?

 

[Jeremy Bopp]

Found way:

b = []
a[3...7].size.times do b.push("B") end
a[3...7] = b

is there anything simplier?

Not necessarily any simpler, but perhaps a bit more efficient:

3...7.each { |i| a = "B" }

Wrap it up into a nice method:

class Array
def replace_range_with(range, replacement)
range.each { |i| self = replacement }
self
end
end

a = ["A", "A", "A", "A", "A"]
a.replace_range_with(2...4, "B") #=> ["A", "A", "B", "B", "A"]


-Jeremy

 

[Ruby Fan]

Jeremy,

Thank you! It's very nice )

 

[botp]

Found way:

b =3D []
a[3...7].size.times do b.push("B") end
a[3...7] =3D b

3...7.each { |i| a =3D "B" }

class Array
=A0def replace_range_with(range, replacement)
=A0 =A0range.each { |i| self =3D replacement }
=A0 =A0self
=A0end
end
a =3D ["A", "A", "A", "A", "A"]
a.replace_range_with(2...4, "B") #=3D> ["A", "A", "B", "B", "A"]

in some cases, specifying the starting and the length may be also handy, e=
g,

a=3D["A"]*10
#=3D> ["A", "A", "A", "A", "A", "A", "A", "A", "A", "A"]

a[3,4]=3D["B"]*4
#=3D> ["B", "B", "B", "B"]

a
#=3D> ["A", "A", "A", "B", "B", "B", "B", "A", "A", "A"]

and ff jeremy's wrapping,

class Array
def replacex start,length, item
self[start,length]=3D[item]*length
end
end
#=3D> nil

a=3D["A"]*10
#=3D> ["A", "A", "A", "A", "A", "A", "A", "A", "A", "A"]

a.replacex 3, 4,"B"
#=3D> ["B", "B", "B", "B"]

a
#=3D> ["A", "A", "A", "B", "B", "B", "B", "A", "A", "A"]


best regards -botp

 

[Nagachaitanya Vellanki]

You can use the fill method in the Array class

e.g from the Ruby docs

a.fill("z", 2, 2) #=> ["x", "x", "z", "z"]
a.fill("y", 0..1) #=> ["y", "y", "z", "z"]

Please refer to the Ruby docs for other ways to use the fill method

http://railsapi.com/doc/ruby-v1.9.2/classes/Array.html#M000097