To change all the elements of an array in Groovy, you can loop through the array and update each element. Here's an example:
def nums = [1, 2, 3, 4, 5]
nums.eachWithIndex { num, index ->
nums[index] = num * 2
}
println nums // output: [2, 4, 6, 8, 10]
In this example, we first define an array of numbers nums. We then use the eachWithIndex method to loop through the array, which allows us to access both the current element (num) and its index (index). We then update each element in the array by multiplying it by 2 and assigning it back to the same index.
Alternatively, you can also use the collect method to create a new array with the updated values:
def nums = [1, 2, 3, 4, 5]
def doubled = nums.collect { num -> num * 2 }
println doubled // output: [2, 4, 6, 8, 10]
In this example, we use the collect method to create a new array doubled with the updated values. The collect method loops through each element of the array and applies the specified closure (which multiplies the value by 2) to each element, creating a new array of the resulting values.