Introduction

Loops are essential control structures in programming that allow you to execute a block of code repeatedly. In Groovy, a versatile and dynamic language, loops come in different flavors to cater to various scenarios. In this blog post, we’ll explore the loops available in Groovy, including for, while, and each, and show you how to use them effectively.

The for Loop

The for loop in Groovy is used to iterate over a range of values, a collection, or any iterable object. It has a flexible syntax that allows you to specify the loop variable, the range or collection to iterate over, and the code block to execute for each iteration.

Here’s the basic structure of a for loop:

for (item in collection) {
    // Code to execute for each item in the collection
}

Example 1: Iterating over a Range

for (i in 1..5) {
    println("Iteration $i")
}

Example 2: Iterating over a List

def fruits = ["apple", "banana", "cherry"]
for (fruit in fruits) {
    println("Fruit: $fruit")
}

The while Loop

The while loop in Groovy repeatedly executes a block of code as long as a specified condition is true. It’s useful when you don’t know in advance how many times the loop should run.

Here’s the basic structure of a while loop:

while (condition) {
    // Code to execute while the condition is true
}

Example: Counting Down

def count = 5
while (count > 0) {
    println("Countdown: $count")
    count--
}

The each Method

In Groovy, many iterable objects, such as lists and maps, have an each method that allows you to iterate over their elements conveniently.

Example: Using each with a List

def fruits = ["apple", "banana", "cherry"]
fruits.each { fruit ->
    println("Fruit: $fruit")
}

Example: Using each with a Map

def person = [name: "Alice", age: 30]
person.each { key, value ->
    println("$key: $value")
}

Loop Control Statements

In addition to the basic loop constructs, Groovy provides control statements like break and continue to fine-tune loop behavior.

for (i in 1..10) {
    if (i == 5) {
        break
    }
    println("Iteration $i")
}
for (i in 1..10) {
    if (i % 2 == 0) {
        continue
    }
    println("Odd number: $i")
}

Conclusion

Loops are indispensable tools in Groovy programming, enabling you to perform repetitive tasks efficiently. By mastering the use of for, while, and each loops, along with loop control statements, you can write code that is more expressive, concise, and adaptable to various scenarios. Whether you’re processing data, automating tasks, or building complex algorithms, Groovy’s loop constructs are your allies in creating dynamic and efficient programs. Happy coding!

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