Dictionary of lists to list of tuples

Question

t = {"Harvard": [43280, 51143], "Brown": [53419, 62680], "Columbia": [10968, 30257]}

t_pct_change = round((end - start)/start * 100, 2)

list_tuples = [(k, round((t[k][-1] - t[k][0])/t[k][0] * 100, 2)) for k in t for v in t[k]]

The end is the first index of the list and the start is the last index of the list. I want the result to be a list of tuples like

[('Harvard', 18.17), ('Brown', 17.34), ('Columbia', 175.87)]

My code iterates 3 times. How do I fix this or is there a better way to do this?

Answer 1

You just need to loop once over the dictionary using t.items().

You can also unpack the values so you have nice meaningful names instead of indices.

t = {"Harvard": [43280, 51143], "Brown": [53419, 62680], "Columbia": [10968, 30257]}
my_list = [(uni, round((end - start)/start * 100, 2)) for uni, (start, end) in t.items()]
print(my_list)

Expected output:

[('Harvard', 18.17), ('Brown', 17.34), ('Columbia', 175.87)]