How do I pass an array in ARGV command line arguments? - ruby

Question

I have the following:
=== My program test.rb
def test (app, download, launch )
for i in 0..(app.length - 1)do
#DO SOMETHING HERE WITH THIS
p app[i].to_s + download[i].to_s + launch[i].to_s
end
end
test (ARGV[0].split(//) , ARGV[2].split(//) ,ARGV[1].split(//))
=== other program "other.rb" that parses and executes test.rb
app = ["fda","asdf"]
down = ["ok","nok"]
la = ["ok","ok"]
system("ruby test.rb #{app} #{down} #{la}")
I would like to print it as something like this:
fda ok ok
asdf no nok
However it is printed like this:
foo
dkk
ano
aok
sk
d
f
How can I pass arrays to the app correctly?

Answer 1

I copied your source and pasted it into two files:
test.rb:
def test (app, download, launch )
for i in 0..(app.length - 1)do
#DO SOMETHING HERE WITH THIS
p app[i].to_s + download[i].to_s + launch[i].to_s
end
end
test (ARGV[0].split(//) , ARGV[2].split(//) ,ARGV[1].split(//))
and test2.rb:
app = ["fda","asdf"]
down = ["ok","nok"]
la = ["ok","ok"]
system("ruby test.rb #{app} #{down} #{la}")
Using Ruby 1.9.2p290, I get this result when I run your code:
ruby test2.rb
test.rb:7: syntax error, unexpected ',', expecting ')'
test (ARGV[0].split(//) , ARGV[2].split(//) ,ARGV[1].split(//))
^
test.rb:7: syntax error, unexpected ',', expecting $end
test (ARGV[0].split(//) , ARGV[2].split(//) ,ARGV[1].split(//))
That tells me you didn't accurately report the problem you're seeing.
Fixing the syntax error returns this:
ruby test2.rb
"[[a"
"fos"
"dkd"
"a,f"
",]"
The output I got is what I would expect from your code, however it doesn't resemble what you said you got, so I doubt your reported output is correct. Please be accurate when you ask for help, both in the code you've written and the output you've seen.
Looking at the data your code is passing shows the arguments are:
0 [fda,
1 asdf]
2 [ok,
3 nok]
4 [ok,
5 ok]
FYI, I got those using this bit of code in place of test.rb:
ARGV.each_with_index do |a, i|
puts "#{i} #{a}"
end
I'd expect that, because system("ruby test.rb #{app} #{down} #{la}") doesn't do what you think it does. Here is what the actual command sent to the sub-shell looks like when system processes it:
test.rb [fda, asdf] [ok, nok] [ok, ok]
Again, that matches what the arguments look like when the app sees them.
To understand what is happening, you need to read the documentation for system:
system([env,] command... [,options]) -> true, false or nil
[...]
command... is one of following forms.
[...]
cmdname, arg1, ... : command name and one or more arguments (no shell)
So, system allows us to send all the parameters separately, which is really what you want. Changing test2.rb to:
app = %w[ fda asdf ]
down = %w[ ok nok ]
la = %w[ ok ok ]
system(
"echo",
"test.rb",
%Q["#{ app.join(',') }"],
%Q["#{ down.join(',') }"],
%Q["#{ la.join(',') }"]
)
gives me this on the command-line:
ruby test2.rb
test.rb "fda,asdf" "ok,nok" "ok,ok"
Which seems a bit more usable. Because of how system works, I can clean it up and reduce that a bit to:
app = %w[ fda asdf ]
down = %w[ ok nok ]
la = %w[ ok ok ]
system(
"ruby", # execute this
"test.rb", # with this script name
app.join(','), down.join(','), la.join(',') # and these parameters
)
Looking at what test.rb sees shows:
ruby test2.rb
0 fda,asdf
1 ok,nok
2 ok,ok
Again, an improvement and closer to what your code expected.
I am not going to finish correcting your code because I suspect this is a homework assignment and not a practical use. Some hints to help you are:
Your use of split isn't correct, nor is it where I would put it.
Your use of for is not idiomatic Ruby. Look at Array.each AND learn why it is preferred instead of for.
Your use of to_s is unnecessary, since you are already dealing with strings and characters.

Answer 2

you could use Thor which is a dsl for creating command line apps