Groovy: Strings

Strings are collection of characters. Groovy supports 3 types of strings.

a.   Single Quoted Strings

b.   Double Quoted Strings

c.    Triple Quoted Strings

Single Quoted Strings

Collection of characters surrounded by single quotes. These string are instances of ‘java.lang.String’ class.

HelloWorld.groovy

String message = 'Hello World'

println message
println message.class

Output

Hello World

class java.lang.String

Double Quoted Strings

Collection of characters surrounded by double quotes.

HelloWorld.groovy

String message = "Hello World"

println message
println message.class

Output

Hello World

class java.lang.String

Double quoted strings support string interpolation. Interpolation is a technique to replace the value of an expression or variable upon evaluation of a string.

How to write interpolate expressions?

Surround the expression by ${} or prefix with $ for dotted expressions.

HelloWorld.groovy

String name = "Krishna"
int age = 29

String result = "Hello Mr.${name}, you are ${age} years old"

println result

Output

Hello Mr.Krishna, you are 29 years old

Double quoted strings are instances of java.lang.String if there’s no interpolated expression, but are instances of groovy.lang.GString instances if interpolation is present.

Can I insert multiple statements in a placeholder?

Yes, you can insert multiple statements in a placeholder.

HelloWorld.groovy

println "Sum of 1 and 2 is ${int a = 1, b = 2; a + b}"
println "Subtraction of 1 and 2 is ${int a = 1, b = 2; a - b}"
println "Multiplicaion of 1 and 2 is ${int a = 1, b = 2; a * b}"
println "Division of 1 and 2 is ${int a = 1, b = 2; a / b}"

$ sign prefixing a dotted expression

HelloWorld.groovy

class Employee{
	String firstName
	String lastName
}

Employee emp = new Employee()
emp.firstName = "krishna"
emp.lastName = "Gurram"

println "Employee first name $emp.firstName, last name $emp.lastName"

Output

Employee first name krishna, last name Gurram

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