How would I translate this JavaScript code to Python code?

As python is an object oriented language, the way to get an object is basically to create a class which acts as the blueprint/prototype for different instantiations of that object. So your code translated to python could look more or less like this:

(all of you python pros, please forgive me, I'm not =D)

class MyCache:
    def __init__(self, *args, **kwargs):
        # in python the most similar to a javascript array is a list
        # to make it a bit more readable `myArray` is called `_cache` here
        self._cache = []

    def add(self, x):
        # do not try to pop() from an empty list, will throw an error
        if self._cache:
            self._cache.pop(0)

        self._cache.append(x)

    def access(self, z):
        # index() is a bit whimpy in python...
        try:
            i = self._cache.index(z);
            # I think we don't need the .slice() stuff here,
            # can just .pop() at the index in python
            self._cache.pop(i)
            self._cache.append(z)
        except ValueError as err:
            print(err)

    def size(self, y):
        # not sure what you want to do here, initialize the cache with
        # an array/list of a specific length?
        self._cache = [None] * y

    # print is a reserved word in python...
    def status(self):
        print("Current array is: ")
        print(self._cache)

# instantiate the class (e.g. get a cache object)
# and do some stuff with it..
cache = MyCache()
cache.add(7)
cache.status()
cache.add(10)
cache.status()
cache.add(3)
cache.status()
cache.access(3)
cache.status()

not sure if this is actually doing what you're expecting it to do, you'll always have only 1 value in the cache because the add() method will always remove one...so the access method kind of doesn't make sense...but maybe it was just your simplified example code?