Idiomatic Printing an array with commas

[Chuck Brotman]

Hi,

I want to print an array (of strings, mostly) with commas separating the
elements (so it would look like the result in the irb

a =[one,two,three]
printspecial a # should produce "[one, two, three]" not "onetwothree"
as it # currently does


I tried a.map{|s| s.to_s + ", "
but this gives me [one, two, three,]
with an extra comma trailing the last element

Is there a nice ruby idiom to do what I want (or to simply produce the
necessary string for printing?

Or, do I have to resort to an explicit loop checking for the last
element and not alter it?

 

[Dominik Honnef]

Hi,

I want to print an array (of strings, mostly) with commas separating the
elements (so it would look like the result in the irb
[snip]


Is there a nice ruby idiom to do what I want (or to simply produce the
necessary string for printing?

a = ["one", "two", "three"]
puts a.inspect
puts "[" + a.join(", ") + "]"

# >> ["one", "two", "three"]
# >> [one, two, three]

 

[Brian Candler]

I want to print an array (of strings, mostly) with commas separating the
elements (so it would look like the result in the irb

You want String#inspect. (irb calls #inspect on the object it's
displaying)

$ irb --simple-prompt

a = ["one","two","three"] => ["one", "two", "three"]
puts a.inspect

["one", "two", "three"]
=> nil

 

[リヴェリエ]

[Note: parts of this message were removed to make it a legal post.]

You can always try a * ", "

% irb --simple-prompt

a = ["a","b","c"] => ["a", "b", "c"]
a * ", "

=> "a, b, c"

 

[Josh Cheek]

[Note: parts of this message were removed to make it a legal post.]

Hi,

I want to print an array (of strings, mostly) with commas separating the
elements (so it would look like the result in the irb

a =[one,two,three]
printspecial a # should produce "[one, two, three]" not "onetwothree"
as it # currently does


I tried a.map{|s| s.to_s + ", "
but this gives me [one, two, three,]
with an extra comma trailing the last element

Is there a nice ruby idiom to do what I want (or to simply produce the
necessary string for printing?

Or, do I have to resort to an explicit loop checking for the last
element and not alter it?

As other people have pointed out, you are looking for the inspect method. If
you are wanting to print it
p a
puts a.inspect

are the same thing.




As far as your issue with the comma after the last element, the join method
will do what you were trying to do with map, except it won't put it on the
last element.

a.join(', ') # => "1, 2, 3"

 

[Chuck Brotman]

I tried it and that appears to be exactly what I need!!

Thank you very much!!!

You want String#inspect. (irb calls #inspect on the object it's
displaying)

$ irb --simple-prompt

a = ["one","two","three"] => ["one", "two", "three"]
puts a.inspect

["one", "two", "three"]
=> nil

 

[Chuck Brotman]

".inspect", ".join", "*". Of course, there isn't just one way to get
the job done in Ruby!

I appreciate all the tips


Thanks,

Chuck