Methods optional arguments

[Ibon Castilla]

Hi there:

I was learning about methods, and when I was trying to use optional
arguments I get stucked with this:

def my_method (a='This', b='is', c='great')
puts a+' '+b+' '+c
end

If I try:
my_method('Ruby')
-> Ruby is great
-> nil

But if I try:
my_method(,,'cool')
-> SyntaxError: compile error

Any idea on how to use arguments different from the first one?.

Thank's in advance, Ibon.

 

[Michael Morin]

Hi there:

I was learning about methods, and when I was trying to use optional
arguments I get stucked with this:

def my_method (a=3D'This', b=3D'is', c=3D'great')
=A0puts a+' '+b+' '+c
end

If I try:
=A0my_method('Ruby')
=A0-> Ruby is great
=A0-> nil

But if I try:
=A0my_method(,,'cool')
=A0-> SyntaxError: compile error

Any idea on how to use arguments different from the first one?.

Thank's in advance, Ibon.

Optional arguments must be passed in the order they're declared, and
cannot be omitted. Instead, you'll often see hashes used instead.

def my_method(options=3D{})
o =3D {
:a =3D> 'This',
:b =3D> 'is',
:c =3D> 'cool'
}.merge(options)

puts "#{o[:a]} #{o[:b]} #{o[:c]}"
end

my_method( :c =3D> 'great' )

 

[Brian Candler]

�my_method('Ruby')

Optional arguments must be passed in the order they're declared, and
cannot be omitted. Instead, you'll often see hashes used instead.

def my_method(options={})
o = {
:a => 'This',
:b => 'is',
:c => 'cool'
}.merge(options)

puts "#{o[:a]} #{o[:b]} #{o[:c]}"
end

my_method( :c => 'great' )

I agree that's probably the best approach in most cases. If you really
want 'optional' earlier arguments, you'd have to do something like this:

def my_method(a=nil, b=nil, c=nil)
a ||= 'This'
b ||= 'is'
c ||= 'great'
puts a+' '+b+' '+c
end

p my_method(nil, nil, 'cool')

 

[Ibon Castilla]

Hi both:

Thanks for the code. I'll print it out to keep it safe, and not to hold
on my memory

Cheers, Ibon.