Ruby output contents of an array as a comma separated string Ruby

Question

Is there a more correct way to output the contents of an array as a comma delimited string

@emails = ["joe@example.com", "Peter@example.com", "alice@example.com"]

@emails * ","

=> "joe@example.com", "Peter@example.com", "alice@example.com"

This works but I am sure there must be a more elegant solution.

Answer 1

你试过这个：

@emails.join(",")

Answer 2

Though the OP and many answers imply that the array always has content, sometimes I find myself needing to join a list that may contain "empty" elements (typically for concatenating data for a UI).

Here is little "progression" of how different approaches handle such an "imperfect" array of strings:

['a','b','',nil].join(',') # => "a,b,," 
['a','b','',nil].compact.join(',') # => "a,b,"
['a','b','',nil].compact.reject(&:empty?).join(',') # => "a,b"
['a','b','',nil].reject(&:blank?).join(',') # Rails only

The last one being my favorite (Rails) approach.

Answer 3

I just had to do something similar in an ERB template using AllowedUsers <%= _allowed_users.join(" ") %> . It might not be as elegant as you were looking for, but it's the same implementation I've seen in several languages, so that might be a win for readability.