Question

I am new to Groovy. I execute the following Groovy code:

myList=[234, 34, "Stackoverflow", 3.14]

myList=myList.collect {if (it instanceof Integer) it*it}     

println myList

it outputs:

[54756, 1156, null, null]

It seems to me that it shouldn’t change the strings value. when I change the second line to:

myList=myList.collect {if (it instanceof Integer) it*it else it=it}

it works as I expected:

[54756, 1156, Stackoverflow, 3.14]

I am wondering what is the logic behind that!

Answer 1

Since there is no else clause in your first version, null is the result.

The second version should work like this, too:

myList.collect {if (it instanceof Integer) it * it else it}