Using Substitution Expressions in Strings
Groovy supports using two kinds of string literals, normal strings and strings with substitution expressions. To define a normal string literal, use single quotes to surround the contents like this:
// These are normal strings
def name = 'Steve'
def confirmation = '2 message(s) sent to ' + name
To define a string with substitution expressions, use double-quotes to surround the
contents. The string value can contain any number of embedded expressions using the
${
expression
}
syntax. For
example, you could write:
// The confirmation variable is a string with substitution expressions
def name = 'Steve'
def numMessages = 2
def confirmation = "${numMessages} message(s) sent to ${name}"
Executing the code above will end up assigning the value 2 messages(s) sent to
Steve to the variable named confirmation
. It does no harm to
use double-quotes all the time, however if your string literal contains no substitution
expressions it is slightly more efficient to use the normal string with single-quotes.