Single quoted string to become double quoted - is it possible?

Ruby
1

Hello, Ruby experts.
Imagine I have single quoted string:
a = ‘bla bla #{name} bla bla’
name = ‘Andrew’
Is it possible to make a act as double quoted string: puts a => ‘bla bla
Andrew bla bla’ instead of’ bla bla #{name} bla bla’?

2

This is terrible, but:

eval “”#{a}""

3

Thank you, Steve. It works fine.

4

On Sun, Dec 18, 2011 at 05:20:19AM +0900, ANDREW BIZYAEV (GMAIL) wrote:

Hello, Ruby experts.
Imagine I have single quoted string:
a = ‘bla bla #{name} bla bla’
name = ‘Andrew’
Is it possible to make a act as double quoted string: puts a => ‘bla
bla Andrew bla bla’ instead of’ bla bla #{name} bla bla’?

Why do you need to use single quotes? If you just want to avoid using
double quotes (perhaps because you want double quotes within the
string),
you could use something like this instead:

name = 'Andrew'
puts %Q{blah blah #{name} blah blah}

If you want to be able to reuse the string, you could define a method:

def a(name_input)
  %Q{blah blah #{name_input} blah blah}
end

name = 'Andrew'

puts a(name)
5

On 18.12.2011, at 0:03, Chad P. wrote:

On Sun, Dec 18, 2011 at 05:20:19AM +0900, ANDREW BIZYAEV (GMAIL) wrote:

Hello, Ruby experts.
Imagine I have single quoted string:
a = ‘bla bla #{name} bla bla’
name = ‘Andrew’
Is it possible to make a act as double quoted string: puts a => ‘bla
bla Andrew bla bla’ instead of’ bla bla #{name} bla bla’?

Why do you need to use single quotes?
I use yaml configuration file. in this file I set string template like
this:
:event:
:template: “bla bla #{name} bla bla” #in order to be flexible

Then I load this yaml into @options variable and define @template:
@template = @options[:event][:template] #=> “bla bla #{name} bla bla” So
the effect is the same as using single quotes. And it seems I cannot
change the way Ruby reads yaml strings.
Later in my program I want to use the @template to generate string with
real value of name.
I use Steve’s approach and it works fine:
a = eval “/”#{template}/"" # => “bla bla Andrew bla bla”

 %Q{blah blah #{name_input} blah blah}

end

name = ‘Andrew’

puts a(name)

Thank you for advice. You see I have some other case.

6

On Sat, Dec 17, 2011 at 3:29 PM, ANDREW BIZYAEV (GMAIL) <
[email protected]> wrote:

Later in my program I want to use the @template to generate string with
real value of name.
I use Steve’s approach and it works fine:
a = eval “/”#{template}/"" # => “bla bla Andrew bla bla”

Use a templating language instead:

data = ’
:event:
:template: “bla bla <%= name %> bla bla” #in order to be flexible
’

require ‘yaml’
yaml = YAML.load data
yaml # => {:event=>{:template=>“bla bla <%= name %> bla bla”}}
to_parse = yaml[:event][:template] # => “bla bla <%= name %> bla bla”

require ‘erb’
name = “Jefferson”
ERB.new(to_parse).result # => “bla bla Jefferson bla bla”

note that you may have to pass a binding depending on how you want to

use
it.

7

On Sun, Dec 18, 2011 at 06:29:11AM +0900, ANDREW BIZYAEV (GMAIL) wrote:

double quotes (perhaps because you want double quotes within the string),

name = ‘Andrew’

puts a(name)

Thank you for advice. You see I have some other case.

Yeah, I see that now. I think, for that use case, I’d probably do some
parse-and-replace on any strings loaded from the YAML, rather than eval
every string from YAML – it’s safer. Any time you think eval is the
right answer to something, it pays to think three or four more times
before you decide you’re sure, especially if there’s any possibility
of
arbitrary data getting into what you’re going to eval.

8

Use a templating language instead:

Or a string substitution:

string = “blah blah blah NAME blah blah blah”
name = “Andrew”
string.sub! “NAME”, name