CODEWITHSUNDEEP
ruby-on-railsruby
chug2k
chug2k

Reputation: 5220

Breaking up long strings on multiple lines in Ruby without stripping newlines

We recently decided at my job to a ruby style guide. One of the edicts is that no line should be wider than 80 characters. Since this is a Rails project, we often have strings that are a little bit longer - i.e. "User X wanted to send you a message about Thing Y" that doesn't always fit within the 80 character style limit.

I understand there are three ways to have a long string span multiple lines:

However, all of these cases end up taking more computation cycles, which seems silly. String concatenation obviously, but for HEREDOC and %Q I have to strip out the newlines, via something like .gsub(/\n$/, '').

Is there a pure syntax way to do this, that is equivalent to just having the whole string on one line? The goal being, obviously, to not spend any extra cycles just because I want my code to be slightly more readable. (Yes, I realize that you have to make that tradeoff a lot...but for string length, this just seems silly.)

Update: Backslashes aren't exactly what I want because you lose indentation, which really affects style/readability.

Example:

if foo
  string = "this is a \  
string that spans lines"  
end

I find the above a bit hard to read.

EDIT: I added an answer below; three years later we now have the squiggly heredoc.

Upvotes: 302

Views: 178347

Answers (9)

Jamie
Jamie

Reputation: 1937

If you want to use backslash, and want to indent your strings, just wrap them in quotes:

str = "This is a multi" \
      "line string!"
puts str

This is a multiline string!

Upvotes: 1

viktorianer
viktorianer

Reputation: 102

Squish in Rails is doing what you need.

https://apidock.com/rails/String/squish

End it looks like this:

%{ Multi-line
   string }.squish

And because you need it in Ruby, just look at Rails code:

%{ Multi-line
   string }
  .gsub!(/[[:space:]]+/, " ")
  .strip!

Upvotes: 3

geoff
geoff

Reputation: 456

This is by now a very old question but as the issue still seems to come up here's an updated answer. Since the original poster indicated this was for a Rails project you can look to Rails' String inflections for help.

my_long_string = <<-STRING
 hello
    there
 multiline
      multiindented string
STRING

=> " hello\n    there\n multiline\n      multiindented string\n"

Enter the squish method.

my_long_string = <<-STRING.squish
 so
    long
 multiline
      multiindented string
STRING

=> "so long multiline multiindented string"

As per the docs -

squish() Returns the string, first removing all whitespace on both ends of the string, and then changing remaining consecutive whitespace groups into one space each.

Upvotes: 28

Addin Cui
Addin Cui

Reputation: 83

You can concatenate multiple strings split over several lines:

if foo
  string = "this is a" + 
           "string that spans lines"  
end

Upvotes: 0

Jon Snow
Jon Snow

Reputation: 11872

I had this problem when I try to write a very long url, the following works.

image_url = %w(
    http://minio.127.0.0.1.xip.io:9000/
    bucket29/docs/b7cfab0e-0119-452c-b262-1b78e3fccf38/
    28ed3774-b234-4de2-9a11-7d657707f79c?
    X-Amz-Algorithm=AWS4-HMAC-SHA256&
    X-Amz-Credential=ABABABABABABABABA
    %2Fus-east-1%2Fs3%2Faws4_request&
    X-Amz-Date=20170702T000940Z&
    X-Amz-Expires=3600&X-Amz-SignedHeaders=host&
    X-Amz-Signature=ABABABABABABABABABABAB
    ABABABABABABABABABABABABABABABABABABA
).join

Note, there must not be any newlines, white spaces when the url string is formed. If you want newlines, then use HEREDOC.

Here you have indentation for readability, ease of modification, without the fiddly quotes and backslashes on every line. The cost of joining the strings should be negligible.

Upvotes: 23

iheggie
iheggie

Reputation: 2047

I modified Zack's answer since I wanted spaces and interpolation but not newlines and used:

%W[
  It's a nice day "#{name}"
  for a walk!
].join(' ')

where name = 'fred' this produces It's a nice day "fred" for a walk!

Upvotes: 19

chug2k
chug2k

Reputation: 5220

Three years later, there is now a solution in Ruby 2.3: The squiggly heredoc.

class Subscription
  def warning_message
    <<~HEREDOC
      Subscription expiring soon!
      Your free trial will expire in #{days_until_expiration} days.
      Please update your billing information.
    HEREDOC
  end
end

Blog post link: https://infinum.co/the-capsized-eight/articles/multiline-strings-ruby-2-3-0-the-squiggly-heredoc

The indentation of the least-indented line will be removed from each line of the content.

Upvotes: 60

Jessehz
Jessehz

Reputation: 5232

Maybe this is what you're looking for?

string = "line #1"\
         "line #2"\
         "line #3"

p string # => "line #1line #2line #3"

Upvotes: 554

Emily
Emily

Reputation: 18193

You can use \ to indicate that any line of Ruby continues on the next line. This works with strings too:

string = "this is a \
string that spans lines"

puts string.inspect

will output "this is a string that spans lines"

Upvotes: 72

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