Begineer question

[jim o]

I have had a horrible time googling this as I get too many hits back that don't apply.



I am new to Ruby, and trying to find a good ref as for when one would use the form



puts #{a}

vs
puts a

Does anyone have any pointers?

Thanks
Jim






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[Felipe Contreras]

I have had a horrible time googling this as I get too many hits back that don't apply.



I am new to Ruby, and trying to find a good ref as for when one would use the form



puts #{a}

vs
puts a

Does anyone have any pointers?

You mean:
puts "#{a}"

Right? If so then it simply helps to do:

puts "foo=#{a} allows you to do more interesting things"

If you just want to print 'a' then there's no reason to do "#{a}" it
would be like doing "%s" % [a]; you can do it, but it doesn't make
sense.

 

[Sebastian Hungerecker]

I am new to Ruby, and trying to find a good ref as for when one would use
the form

puts #{a}
vs
puts a

puts #{a} doesn't do anything (except return nil), so I'm going to assume you
meant to say puts "#{a}". Since that does the same thing as puts a but is more
to type, I'd always use the latter. The #{} syntax is only useful when you
want to print out more than just the content of the variable. For example:
puts "The value of x is #{x}"

 

[Harry Kakueki]

puts #{a}

vs
puts a

Does anyone have any pointers?

Thanks
Jim

This will explain a little more about what Sebastian showed you.

http://www.rubycentral.com/book/tut_stdtypes.html#S2

Harry

 

[Chad Perrin]

puts #{a} doesn't do anything (except return nil), so I'm going to assume you
meant to say puts "#{a}". Since that does the same thing as puts a but is more
to type, I'd always use the latter. The #{} syntax is only useful when you
want to print out more than just the content of the variable. For example:
puts "The value of x is #{x}"

It really takes a more complex example to really make using that syntax
worthwhile. After all, these are equivalent:

puts "The value of foo is #{foo}"
puts "The falue of foo is " + foo

. . except that the second example doesn't require as much use of the
Shift key.

Yeah, though -- your example does make the point clear. I guess I'm
just being a touch pedantic.

 

[Robert Dober]

I have had a horrible time googling this as I get too many hits back that don't apply.



I am new to Ruby, and trying to find a good ref as for when one would use the form



puts #{a}

vs
puts a

Does anyone have any pointers?

You mean:
puts "#{a}"

Right? If so then it simply helps to do:

puts "foo=#{a} allows you to do more interesting things"

If you just want to print 'a' then there's no reason to do "#{a}" it
would be like doing "%s" % [a]; you can do it, but it doesn't make
sense.

Well maybe it might be useful to explain things a little more in
detail, because there is #to_s called all over the place
As a matter of fact "#{a}" is the same as "" << a.to_s
and IO#puts, IO#write and IO#print convert their arguments by
calling#to_s on them too.

It is therefore only in the context of e.g. puts that
"#{a}" is the same as a.

HTH
Robert

 

[Sebastian Hungerecker]

After all, these are equivalent:

puts "The value of foo is #{foo}"
puts "The falue of foo is " + foo

Only if foo is a string. #{} automatically to_ses non-strings, while + doesn't

 

[Lloyd Linklater]

Perhaps a translation would make things clearer:

printf("We are going to %s.", [toUpper(destination)]);

puts "We are going to #{destination.upcase}."

 

[Robert Dober]

Perhaps a translation would make things clearer:

printf("We are going to %s.", [toUpper(destination)]);

puts "We are going to #{destination.upcase}."

Maybe print is better a translation, but you made your point nonetheless

Robert