A complete beginners question

Ruby
1

Hi there,

Sorry this is probably going to be a real easy question but I am totally
new to programming.

I was following some tutorial online and at the end of the first chapter
it said 'Now create a program that asks the user for a number and then
suggests a higher number as a better option.

So what I wanted to happen below is it takes the users input and just
adds 1 to it. But is is coming back with "rb:3:in ‘+’ can’t convert
fixnum into string’

puts ‘What is your favourite number?’
number = gets.chomp
number+=1
puts ‘Do you not think’ + number + ‘is a better number?’

Any help would be appreciated its doing my head in.

Thanks

2

On Sat, May 29, 2010 at 03:29:15AM +0900, Ant Walliams wrote:

Hi there,
puts ‘What is your favourite number?’
number = gets.chomp
number+=1
puts ‘Do you not think’ + number + ‘is a better number?’
puts ‘Do you not think’ + number.to_s + ‘is a better number?’

3

Reid T. wrote:

On Sat, May 29, 2010 at 03:29:15AM +0900, Ant Walliams wrote:

Hi there,
puts ‘What is your favourite number?’
number = gets.chomp
number+=1
puts ‘Do you not think’ + number + ‘is a better number?’
puts ‘Do you not think’ + number.to_s + ‘is a better number?’

Thank for the reply but I am still getting the same error even after
making your changes. Any ideas?

Thanks
Ant

4

On Fri, May 28, 2010 at 8:59 PM, Ant Walliams
[email protected] wrote:

making your changes. Any ideas?

Thanks
Ant

Posted via http://www.ruby-forum.com/.

You need to convert the input from String to Fixnum

puts “What is your favourite number?”
number = gets.chomp.to_i
number+=1
puts “Do you not think #{number} is a better number?”

5

On May 28, 2010, at 2:59 PM, Ant Walliams wrote:

making your changes. Any ideas?

Thanks
Ant

the problem is with number+=1

number is a string because gets.chomp is a string

number+=1 is syntactic sugar for
number = number + 1

And the expression number + 1 is trying to add 1 (a Fixnum) to a string

Try changing:

number = gets.chomp.to_i

to convert the string into an integer (which if small enough will be
held in an instance of Fixnum).

Then, you’ll have the opposite problem with the last line unless you
incorporate Reid’s suggestion.

-Rob

Rob B. http://agileconsultingllc.com
[email protected]

6

Rob B. wrote:

On May 28, 2010, at 2:59 PM, Ant Walliams wrote:

making your changes. Any ideas?

Thanks
Ant

the problem is with number+=1

number is a string because gets.chomp is a string

number+=1 is syntactic sugar for
number = number + 1

And the expression number + 1 is trying to add 1 (a Fixnum) to a string

Try changing:

number = gets.chomp.to_i

to convert the string into an integer (which if small enough will be
held in an instance of Fixnum).

Then, you’ll have the opposite problem with the last line unless you
incorporate Reid’s suggestion.

-Rob

Rob B. http://agileconsultingllc.com
[email protected]

Thank you very much, that worked. And thanks for the explanation of how
it works as well, that really helps.

Thanks
Ant

7

Hi, just do this:

puts “What is your favourite number?”
number = gets.chomp
number+=1
puts “Do you not think #{number.to_s} is a better number?”

Best regards.

8

Hi, i am in Osx and i had installed Ruby 1.8.7. I want to make a
tutorial, i am a beginner in ruby. My problem is that when i want to
execute a program on ruby, example: code.rb, with “ruby code.rb” on
Terminal, like all tutorials sais, a error come back: “-bash: code.rb:
command not found”

Well, there is a part that i am missing. Please help me.

9

Il 29/05/10 21.43, Emma Pidre ha scritto:

Hi, i am in Osx and i had installed Ruby 1.8.7. I want to make a
tutorial, i am a beginner in ruby. My problem is that when i want to
execute a program on ruby, example: code.rb, with “ruby code.rb” on
Terminal, like all tutorials sais, a error come back: “-bash: code.rb:
command not found”

Well, there is a part that i am missing. Please help me.

It’s ok, you want to run it as a normal command if i understand well.
First thing to do, is adding a “shebang”[1] at top of your ruby file.
After that, you have to make it executable, and, to do it you have to
write on bash command line, chmod +x code.rb and voilà , your ruby script
as executable in this way: ./code.rb

Have fun with ruby,
-Francesco

[1] shebang: “/usr/bin/env ruby”

10

On 28/05/10 19:29, Ant Walliams wrote:

adds 1 to it. But is is coming back with "rb:3:in ‘+’ can’t convert

When you call gets.chomp it returns a string (lets say it’s “5”). That
looks like a number to you and me but ruby treats it as text. You need
to tell ruby to make it a number using .to_i.
ie The second line should read gets.chomp.to_i

Then ruby will be adding 5+1 and not “5”+1. I found that a good way to
think of this was to replace “5” with a word or something. Could you do
“hello”+1?

Angus

11

On Sat, May 29, 2010 at 2:43 PM, Emma Pidre
[email protected]wrote:

Expounding on Francesco’s answer:

add a shebang to the top of a file called hello_world.rb

this directs the system(?) to use Ruby to interpret the file

$ echo ‘#!/usr/bin/env ruby’ > hello_world.rb

append a statement that will output “hello world” to hello_world.rb

$ echo ‘puts “hello world”’ >> hello_world.rb

set permissions of hello_world.rb so that you can execute it

$ chmod 755 hello_world.rb

execute hello_world.rb and see that it outputs “hello world”

the ./ in front is important, it says the file is located in the

current
directory
$ ./hello_world.rb
hello world

12

Hi, trhans for the answer. This is not working. I saw that already had
the first line of code in the example i trying to run : “#!/usr/bin/env
ruby”.

The error is the same:
“ruby: No such file or directory – ./code.rb (LoadError)”

The person who sold me the Macbook, said to me that he made some
troubles with ruby. I don’t know what is wrong, maybe is a configuration
troubles or something like that. i can use directly from textMate, but i
want to resolve the problem form Terminal, to be more sure that all work
fine.

there is a way for restart ruby, i mean, unistall o delete all files or
something like that for make a re-install later ? What did you advise
me?

Thanks for all ! :slight_smile: im very happy to find i place where find help.

13

Il 30/05/10 13.20, Josh C. ha scritto:

–

append a statement that will output “hello world” to hello_world.rb

You’re right, maybe my answer can get someone confused, to be 100% sure,
Josh, let me write a ruby script :slight_smile:

ruby_sample.rb:

#!/usr/bin/env ruby

puts “hello world”

and after you’ve to do what Josh say i mean, 3rd and 4th step.

-Francesco

14

On Sun, May 30, 2010 at 12:01 PM, Emma Pidre
[email protected]wrote:

want to resolve the problem form Terminal, to be more sure that all work

Please follow the instructions above, exactly, and let us know whether
the
hello world example works. (ie if it did not work, it should not have
said
anything about code.rb)

15

On Sun, May 30, 2010 at 2:53 PM, Josh C. [email protected]
wrote:

troubles with ruby. I don’t know what is wrong, maybe is a configuration
Posted via http://www.ruby-forum.com/.

Please follow the instructions above, exactly, and let us know whether the
hello world example works. (ie if it did not work, it should not have said
anything about code.rb)

If you are having difficulty following it, this is what it looks like on
my
cmputer:

16

unsubscribe

17

The final solution is look like this:

puts ‘What is your favourite number?’
number = gets.chomp.to_i
number +=1
puts ‘Do you not think #{number} is a better number?’

18

On Mon, May 31, 2010 at 10:53 PM, Guten [email protected] wrote:

The final solution is look like this:

puts ‘What is your favourite number?’
number = gets.chomp.to_i
number +=1
puts ‘Do you not think #{number} is a better number?’

You don’t need chomp.

“1\n”.to_i # => 1
“1”.to_i # => 1

19

----- “Josh C.” [email protected] wrote:

You don’t need chomp.

“1\n”.to_i # => 1
“1”.to_i # => 1

Let’s not forget our double quotes. Also why write so much code?

puts ‘What is your favorite number?’
puts “Bah! #{gets.to_i + 1} is a better number!”

Understand the #{…} is implicitly invoking to_s on the result so it
can be displayed as part of the final string.

20

On Tue, Jun 1, 2010 at 11:35 AM, Wes B. [email protected]
wrote:

Let’s not forget our double quotes. Also why write so much code?

Because when you’re learning to program it’s nice to have stuff teased
apart into separate steps so that every line is doing just one simple
thing,

martin