k = [1,2,3,4,5]
for n in k
  puts n
  if n == 2
    k.delete(n)
  end
end
puts k.join(",")

# Result:
# 1
# 2
# 4
# 5
# [1,3,4,5]

# Desired:
# 1
# 2
# 3
# 4
# 5
# [1,3,4,5]

This same effect happens with the other array iterator, k.each:

k = [1,2,3,4,5]
k.each do |n|
  puts n
  if n == 2
    k.delete(n)
  end
end
puts k.join(",")

has the same output.

The reason this is happening is pretty clear...Ruby doesn't actually iterate through the objects stored in the array, but rather just turns it into a pretty array index iterator, starting at index 0 and each time increasing the index until it's over. But when you delete an item, it still increments the index, so it doesn't evaluate the same index twice, which I want it to.

This might not be what's happening, but it's the best I can think of.

Is there a clean way to do this? Is there already a built-in iterator that can do this? Or will I have to dirty it up and do an array index iterator, and not increment when the item is deleted?