Groovy each() method does not iterate properly - groovy

Question

I came across a strange behavior of the each() method when trying this code:
def xml = new XmlSlurper().parseText('''
<list>
<item a="1">a</item>
<item a="2">b</item>
<item a="1">c</item>
</list>
''')
def i = 0
xml.'**'.findAll { it.#a=='1' }.each {
println "hi" + i
}
The result is only hi0, however I would expect hi0hi1. Is this behavior a bug or per language design? The second result is only provided if I write println "hi" + i++ instead of the current closure body, so when the content is different for each item...

Answer 1

Your i variable is not being incremented because there's nothing that tells it to increment. The way your code is currently written, I would expect the output to be:
hi0
hi0
I think what you are looking for is eachWithIndex, which provides the closure with two arguments - the current item and the index of the item. Your code would then look like this:
def xml = new XmlSlurper().parseText('''
<list>
<item a="1">a</item>
<item a="2">b</item>
<item a="1">c</item>
</list>
''')
xml.'**'.findAll { it.#a=='1' }.eachWithIndex { item, i ->
println "hi" + i
}
This results in an output of:
hi0
hi1