Strings

  • Prefer string interpolation instead of
    string concatenation:[link]

    1.   # bad
    2.   email_with_name = user.name + ' <' + user.email + '>'
    4.   # good
    5.   email_with_name = "#{user.name} <#{user.email}>"

    Furthermore, keep in mind Ruby 1.9-style interpolation. Let’s say you are
    composing cache keys like this:

    1.   CACHE_KEY = '_store'
    3.   cache.write(@user.id + CACHE_KEY)

    Prefer string interpolation instead of string concatenation:

    1.   CACHE_KEY = '%d_store'
    3.   cache.write(CACHE_KEY % @user.id)

  • Avoid using String#+ when you need to
    construct large data chunks. Instead, use String#<<. Concatenation mutates
    the string instance in-place and is always faster than String#+, which
    creates a bunch of new string objects.[link]

    1.   # good and also fast
    2.   story = ''
    3.   story << 'The Ugly Duckling'
    5.   paragraphs.each do |paragraph|
    6.     story << paragraph
    7.   end

  • Use \ at the end of the line instead of +
    or << to concatenate multi-line strings.
    [link]

    1.   # bad
    2.   "Some string is really long and " +
    3.     "spans multiple lines."
    5.   "Some string is really long and " <<
    6.     "spans multiple lines."
    8.   # good
    9.   "Some string is really long and " \
    10.     "spans multiple lines."