Below is an example of a document that consists of lines in the source but without the terminating string that is needed after the “<<” character. This terminator must start in the first column but with the minus “-” sign after the “<<” character, indention can be done on that specific terminator\ as shown below.

print <<-STRING1, <<-STRING2
Con
STRING1
centrate
STRING2

Gives you

Con
centrate

In the next posts, we would discuss strings further for they are considered to be the largest Ruby class, with over 75 standard methods making it the most used data type in the whole of Ruby.

There are more ways of constructing string literals such as %q, %Q and “here documents.” The first two are used to starte single or double-quoted strings such as;

%q/general single-quoted string/ >> general single-quoted string
%Q!general single-quoted string! >> general double-quoted string
%Q{Seconds/day: #{24*60*60}} >> Seconds/day: 86400

The character following the “q” or “Q” is the delimiter that if it is an opening bracket, brace, parenthisis or a less than sign, the string is read tilla matching closing symbol is found, if not it continues on reading till the next ocurence of the same delimiter is found. The last type of string literal is the “here document” shown below.

a String = <<END_OF_STRING
The body of the string is the
input lines up to the one line
that ends with the same text
that followed the ‘<<’
END_OF_STRING

A note to Perl users, strings that contain numbers will not be automatically converted to numbers when used in an expression such as when trying to read numbers from a file like the one below does.

DATA.each do |line|
vals = line.split # split line, storing tokens in val
print vals[0] + vals[1], ” ”
end

If you use a file as input that contains,

2 8
9 6
1 4

You’ll end up with; 28, 96 and 14 where they were treated as strings and not numbers. Using the string#to_i method which converts the string into an integer you get the desired result.

Sample for string#to_i string to integer conversion

DATA.each do |line|
vals = line.split # split line, storing tokens in val
print vals[0].to_i + vals[1].to_i, ” ”
end

Yielding the right answers; 10 15 5