How do I use Groovy collect?

Posted on by Mary Andersen

How do I use Groovy collect?

Groovy – collect()

  1. Syntax. List collect(Closure closure)
  2. Parameters. The Closure expression.
  3. Return Value. The modified list collection.
  4. Example. Following is an example of the usage of this method of the every method − class Example { static void main(String[] args) { def lst = [1,2,3,4]; def newlst = []; newlst = lst.

How do I create a list of objects in Groovy?

A List literal is presented as a series of objects separated by commas and enclosed in square brackets. To process the data in a list, we must be able to access individual elements. Groovy Lists are indexed using the indexing operator []. List indices start at zero, which refers to the first element.

How do I add elements to a list in Groovy?

Groovy – add() Append the new value to the end of this List. This method has 2 different variants. boolean add(Object value) − Append the new value to the end of this List.

What does findAll do in Groovy?

Groovy – findAll() It finds all values in the receiving object matching the closure condition.

How do I loop a List in Groovy?

groovy Collection Operators Iterate over a collection

  1. Example#
  2. Lists. def lst = [‘foo’, ‘bar’, ‘baz’] // using implicit argument lst.each { println it } // using explicit argument lst.each { val -> println val } // both print: // foo // bar // baz.
  3. Iterate with index.
  4. Maps.

How do I sort a List in Groovy?

Groovy – sort()

  1. Syntax. List sort()
  2. Parameters. None.
  3. Return Value. The sorted list.
  4. Example. Following is an example of the usage of this method − class Example { static void main(String[] args) { def lst = [13, 12, 15, 14]; def newlst = lst. sort(); println(newlst); } }

How do I merge two lists in Groovy?

Combine lists using the plus operator The plus operator will return a new list containing all the elements of the two lists while and the addAll method appends the elements of the second list to the end of the first one. Obviously, the output is the same as the one using addAll method.

What is array in Groovy?

An Array is an object that contains elements of similar data type. Groovy reuses the list notation for arrays, but to make such literals arrays, you need to explicitly define the type of the array through coercion or type declaration. You can also create multi-dimensional arrays.

How do I join two lists in Groovy?

What method is used to split the collection in lists Groovy?

Groovy – split() Splits this String around matches of the given regular expression.

What is =~ in Groovy?

In Groovy, the ==~ operator is “Regex match”. Examples would be: “1234” ==~ /\d+/ -> evaluates to true. “nonumbers” ==~ /\d+/ -> evaluates to false.

What is a Groovy closure?

A closure in Groovy is an open, anonymous, block of code that can take arguments, return a value and be assigned to a variable. A closure may reference variables declared in its surrounding scope.

How do I read an array in Groovy?

In Groovy, you can access array item by using square bracket with an index ( [index] ) or using getAt(index) function.

How do I sort strings in Groovy?

How do I loop a list in Groovy?

How do I sort a list in Groovy?

How do you add two collections in Java?

Using the concat() Method. The static method concat() combines two Streams logically by creating a lazily concatenated Stream whose elements are all the elements of the first Stream followed by all the elements of the second Stream.

What is collate Groovy?

collate(int size, int step) Collates this list into sub-lists of length size stepping through the code step elements for each subList. List. collate(int size, int step, boolean keepRemainder) Collates this list into sub-lists of length size stepping through the code step elements for each sub-list.

How do I split a function in Groovy?

Groovy – split()

  1. Syntax. String[] split(String regex)
  2. Parameters. regex – the delimiting regular expression.
  3. Return Value. It returns the array of strings computed by splitting this string around matches of the given regular expression.
  4. Example. Following is an example of the usage of this method −

What is Groovy used for?

Groovy is a scripting language with Java-like syntax for the Java platform. The Groovy scripting language simplifies the authoring of code by employing dot-separated notation, yet still supporting syntax to manipulate collections, Strings, and JavaBeans.

What are the collection types supported by Groovy?

Groovy provides native support for various collection types, including lists , maps or ranges. Most of those are based on the Java collection types and decorated with additional methods found in the Groovy development kit.

What is the use of collect method in Groovy?

Groovy – collect() The method collect iterates through a collection, converting each element into a new value using the closure as the transformer.

How do you use Groovy functions?

Groovy functions 1 Hello World in a function. The def keyword allows use to define a function that we can use in the code. 2 Passing parameters and returning a result. In this example we created a function that was designed to add two numbers and return the result. 3 Defining the type of the parameters of a Groovy function.

How to deal with nested collections in Groovy?

Thanks to the support of property notation for both lists and maps, Groovy provides syntactic sugar making it really easy to deal with nested collections, as illustrated in the following examples: 2.4.2. Spread operator The spread operator can be used to “inline” a collection into another.