[SOLVED] How to insert separator within printf in ruby

Perseus · 12-04-2014, 12:16 PM

Hello to everyone,

I have a ruby script including a printf() separating the fields by commas in this way:

Code:

printf("%d,%s,%s",$1,$2,$3)

How can I set a variable separator inside the printf() in order to do something like this?:

Code:

sep=","
printf("%d sep %s sep %s",$1,$2,$3)

I want to give the command options when run script.

Thanks in advance

smallpond · 12-04-2014, 12:41 PM

Other than that it looks ugly, what's wrong with:

Code:

printf("%d%s%s%s%s",$1,sep,$2,sep,$3)

Perseus · 12-04-2014, 12:57 PM

Hello smalpond,

Thanks for your answer.

Yes. That way works fine!

One more question:
I run the script currently like this:

Code:

Myscript.rb inputfile

How to add the separator as input parameter (optional)? something like:

Code:

Myscript.rb -sep "," inputfile

Thanks again

Perseus · 12-04-2014, 05:17 PM

Testing I've found that I can do it in this way.

Code:

sep=ARG[0]
input=ARG[1]

and the script could be send like this:

Code:

Myscript.rb "," inputfile

Thanks for the help

grail · 12-05-2014, 02:44 AM

Well you could do it that way ... you might want to do some checking around how many parameters were passed to the script otherwise less that 2 will yield odd results and perhaps errors.

As for your original question, I would have said the easiest way would be:

Code:

puts [$1,$2,$3].join(sep)

Perseus · 12-06-2014, 12:26 AM

Hello grail,

Thanks for your help. Following your suggestion I've used
print [$1,$2,$3].join(sep) instead of puts since puts inserts a end of line.

Regarding the options to pass to the script, may you suggest me a way to handle when parameters are passed or not
in the console. I want to use 2 optional parameters (-a and -b and their respective values) and a mandatory one
that is the input file.

To run the script would be like this:

Code:

Script.rb -a "," -b "@" input

Is there a better way than set several "if" conditions to test if one, two or all parameters where passed?

This is how looks what I have so far.

Code:

if ARGV[0][0..1] == "-a" and ARGV[1].length > 0 and ARGV[2][0..1] == "-b" and ARGV[3].length > 0 then 
	...
end

Thanks again for the help.

kevinmilan2014 · 12-06-2014, 05:45 AM

Quote:

printf("the %s jumped over the %s, %d times", "cow", "moon", 2);

And here are three different printf examples, using different methods that are available to you in the Java programming language:

Quote:

System.out.format("the %s jumped over the %s, %d times", "cow", "moon", 2);
System.err.format("the %s jumped over the %s, %d times", "cow", "moon", 2);
String result = String.format("the %s jumped over the %s, %d times", "cow", "moon", 2);

grail · 12-07-2014, 10:58 AM

For parameter checking, I would suggest a similar tactic as with other languages:

1. test number of parameters passed to script (ARGV.length)

2. loop over each one using either 'if' (one or two options) or 'case' (multiple) to check and apply the switches as required

Another idea, based on your current example may also be to test that ARGV.length is always odd (ie. 1, 3, 5) cause if the user were to pass
2 arguments and they were '-a' and the input file, this would cause your if to still be correct but for the script to behave very strangely