nested hash and nil question

i need to pull out some specific values from a nested hash, but nils
are driving me crazy. in the following example, if address_details,
country, administrative_area, locality OR postal_code are nil i get
"The error occurred while evaluating nil.[]"

zip = placemark['address_details']['country']['administrative_area']
['locality']['postal_code']['postal_code_number']

i tried

unless placemark['address_details']['country']['administrative_area']
['locality']['postal_code']['postal_code_number'].nil?

but if anything above postal_code_number is nil i still get the error.
i could check each level but that is really ugly.

is there a easy way to check if postal_code_number exists?

What value should ‘zip’ contain if postal_code_number doesn’t exist (or any of the keys above it)?

If one of the keys in that long nasty chain are nil, you’re going to
get an exception, but if you know an acceptable default value in case
you can’t eval the whole expression, rescue the exception and return
what you want.

If you want it to be an empty string, for instance, you could do:

zip = placemark[‘address_details’][‘country’][‘administrative_area’][‘locality’][‘postal_code’][‘postal_code_number’] rescue ‘’

that will work perfect, thanks