How to access the first and the last elements in a dictionary?

Question

Before posting, I have already gone through Access an arbitrary element in a dictionary in Python, butI'm uncertain about this.

I have a long dictionary and I've to get the values of its first and last keys. I can use dict[dict.keys()[0]] and dict[dict.keys()[-1]] to get the first and last elements, but since the key:value pairs are outputted in a random form(as in the positioning of the key:value pairs is random), will the solution provided in this link always work?

Answer 1

Use an OrderedDict, because a normal dictionary doesn't preserve the insertion order of its elements when traversing it. Here's how:

# import the right class from collections import OrderedDict  # create and fill the dictionary d = OrderedDict() d['first']  = 1 d['second'] = 2 d['third']  = 3  # retrieve key/value pairs els = list(d.items()) # explicitly convert to a list, in case it's Python 3.x  # get first inserted element  els[0] => ('first', 1)  # get last inserted element  els[-1] => ('third', 3)