# Methods and default values

**URL:** <https://www.ruby-forum.com/t/methods-and-default-values/66068>\
**Category:** Ruby\
**Created:** [February 12, 2006, 6:12am UTC](https://www.ruby-forum.com/t/methods-and-default-values/66068 "2006-02-12T06:12:46Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [February 12, 2006, 6:12am UTC](https://www.ruby-forum.com/t/methods-and-default-values/66068/1 "2006-02-12T06:12:46Z")

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Hi all, let’s say that I have a very nice:

class Text  
def initialize(text, bold=“no”, italic=“no”, color=“black”)  
@text=text  
@bold=bold  
@italic=italic  
@color=color  
end  
end

class TextSet  
def initialize  
@texts=Array.new  
end  
def add(text)  
@texts.push(text)  
end  
end

Let’s say I dont want to have a attr\_writer :italic, :bold, :color  
for TextSet because I want my code to look like

foo = TextSet.new  
foo.add(Text.new(“Hello, my name is”))  
foo.add(Text.new(“Jerome”))

as opposed to

foo = TextSet.new  
text1=Text.new(Text.new(“Hello, my name is”))  
text2=Text.new(Text.new(“Jerome”))  
foo.add(text1)  
foo.add(text2)

Ok, you follow me? Now let’s talk about default value for the Text  
constructor.

Let’s say I want my name (Jerome) in green.

I have to do foo.add(Text.new(“Hello, my name is”, "no, "no, “green”)),  
right?

Question: I’d like to get rid of the useless “no”, “no”.  
Is there a way to specify, that I want an instance of the object with  
the default parameters except for one?

Thanks for your ideas

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [February 12, 2006, 6:24am UTC](https://www.ruby-forum.com/t/methods-and-default-values/66068/2 "2006-02-12T06:24:29Z")

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Hey jarnaud,

Using an hash in that case looks like the most obvious option.  
class Text  
def initialize(text, options)  
@text = text  
@bold = options[:bold] || “no”  
@italic = options[:italic] || “no”  
@color = options[:color] || “black”  
end  
end

you use it like that:

foo.add text, {:color =\> “green”}

maybe somebody has some more fancy solution - just wait a bit 🙂

```auto

```

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [February 12, 2006, 11:03am UTC](https://www.ruby-forum.com/t/methods-and-default-values/66068/3 "2006-02-12T11:03:34Z")

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Michael F. wrote:

> Using an hash in that case looks like the most obvious option. class Text  
> def initialize(text, options)  
> @text = text  
> @bold = options[:bold] || “no”

By the way, I assume that the default “no” should be omitted here,  
simply  
using @bold as a boolean value.

Malte

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [February 12, 2006, 12:47pm UTC](https://www.ruby-forum.com/t/methods-and-default-values/66068/4 "2006-02-12T12:47:36Z")

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2006/2/12, removed\_email\_address@domain.invalid [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):

> Hi all, let’s say that I have a very nice:
> 
> class Text  
> def initialize(text, bold=“no”, italic=“no”, color=“black”)  
> @text=text  
> @bold=bold  
> @italic=italic  
> @color=color  
> end  
> end

I’d represent false by nil or false and not “no”. That way you can  
directly use the boolean value.

Text = Struct.new( :text, :bold, :italic, :color )

def Text(t,a)  
x = {:text=\>t,:color=\>:black}.update(a)  
Text.new(\*(Text.members.map{|f| x[f.to\_sym]}))  
end

def Text2(t,a)  
x = a.inject(:text=\>t,:color=\>:black){|h,(k,v)| h[k]=v unless  
k==:text || “no” == v;h }  
Text.new(\*Text.members.map{|f| x[f.to\_sym]})  
end

irb(main):021:0\> Text(“foo”, :bold=\>true)  
=\> #\<struct Text text=“foo”, bold=true, italic=nil, color=:black\>  
irb(main):022:0\> Text2(“foo”, :bold=\>true, :italic=\>“no”)  
=\> #\<struct Text text=“foo”, bold=true, italic=nil, color=:black\>

see also

> **[WebMD - Better information. Better health.](https://www.webmd.com/?KeywordArguments)**
>
> The leading source for trustworthy and timely health and medical news and information. Providing credible health information, supportive community, and educational services by blending award-winning expertise in content, community services, expert...

HTH

robert