Question

This is what I have now – which looks too verbose for the work it is doing.

@title        = tokens[Title].strip! || tokens[Title] if !tokens[Title].nil?

Assume tokens is a array obtained by splitting a CSV line.
now the functions like strip! chomp! et. all return nil if the string was not modified

"abc".strip!    # => nil
" abc ".strip!  # => "abc"

What is the Ruby way to say trim it if it contains extra leading or trailing spaces without creating copies?

Gets uglier if I want to do tokens[Title].chomp!.strip!

Answer 1

I guess what you want is:

@title = tokens[Title]
@title.strip!

The #strip! method will return nil if it didn’t strip anything, and the variable itself if it was stripped.

According to Ruby standards, a method suffixed with an exclamation mark changes the variable in place.

Update: This is output from irb to demonstrate:

>> @title = "abc"
=> "abc"
>> @title.strip!
=> nil
>> @title
=> "abc"
>> @title = " abc "
=> " abc "
>> @title.strip!
=> "abc"
>> @title
=> "abc"