Practical reason for putting hardcoded names in variable call?

ruby-talk
1

Hi all,

I have become aware that this line of code works

puts "I will make a random #{"word"} in brackets" #I don't get the point of
that.

In this particular case, I could have easily just coded:

puts "I will make a random word in brackets"

Is there any advantage to doing the former? I'm not actually defining a
variable. It's just useful as a placeholder in the future when I'm ready
to put a variable in?

Thanks,

Bill

2

I have become aware that this line of code works

puts "I will make a random #{"word"} in brackets" #I don't get the point of
that.

In this particular case, I could have easily just coded:

puts "I will make a random word in brackets"

Exactly.

Is there any advantage to doing the former?

Not in this use case. But keep in mind, the point of #{...} is that an
arbitrary expression can go there, will be evaluated when the
surrounding expression is executed and whatever the result it will be
transformed to a String via #to_s. That use case is much broader than
just inserting a constant string.

puts "I will make #{2 + rand(17)} random words in brackets"

I'm not actually defining a
variable. It's just useful as a placeholder in the future when I'm ready to
put a variable in?

But why do that? You can start with the String constant and later add
the #{...} with the arbitrary expression that you need there.

Cheers

robert

···

On Fri, Sep 15, 2017 at 6:08 PM, Bill Bisco <billbisco@gmail.com> wrote:

--
[guy, jim, charlie].each {|him| remember.him do |as, often| as.you_can
- without end}
http://blog.rubybestpractices.com/

3

Good point Robert; thank you, that would probably be a little better.

···

On Fri, Sep 15, 2017 at 12:38 PM, Robert Klemme <shortcutter@googlemail.com> wrote:

On Fri, Sep 15, 2017 at 6:08 PM, Bill Bisco <billbisco@gmail.com> wrote:

> I have become aware that this line of code works
>
> puts "I will make a random #{"word"} in brackets" #I don't get the point
of
> that.
>
> In this particular case, I could have easily just coded:
>
> puts "I will make a random word in brackets"

Exactly.

> Is there any advantage to doing the former?

Not in this use case. But keep in mind, the point of #{...} is that an
arbitrary expression can go there, will be evaluated when the
surrounding expression is executed and whatever the result it will be
transformed to a String via #to_s. That use case is much broader than
just inserting a constant string.

puts "I will make #{2 + rand(17)} random words in brackets"

> I'm not actually defining a
> variable. It's just useful as a placeholder in the future when I'm
ready to
> put a variable in?

But why do that? You can start with the String constant and later add
the #{...} with the arbitrary expression that you need there.

Cheers

robert

--
[guy, jim, charlie].each {|him| remember.him do |as, often| as.you_can
- without end}
http://blog.rubybestpractices.com/

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