How to make (list, dictionary) in Python

Question

How to make (list, dictionary) from:

n = ('banana', 5, 'apple', 400, 'orange', 250, 'peach', 300)

to :

(fruit -> price)

Example:

for..print all
    banana -> 5
    apple -> 400
    orange -> 250
    peach -> 300

Answer 1

You can use dict and zip:

n = ('banana', 5, 'apple', 400, 'orange', 250, 'peach', 300)

print(dict(zip(n[::2],n[1::2])))
{'orange': 250, 'peach': 300, 'banana': 5, 'apple': 400}

zip(n[::2],n[1::2]) creates [('banana', 5), ('apple', 400), ('orange', 250), ('peach', 300)] then calling dict on the result creates key/value pairings from each tuple.

More efficiently using iter to avoid slicing and creating new lists:

n = ('banana', 5, 'apple', 400, 'orange', 250, 'peach', 300)
it = iter(n)
print(dict(zip(it,it)))

To print the items:

for fruit, cost in dict(zip(it,it)).items():
    print("{} -> {}".format(fruit, cost))

apple -> 400
orange -> 250
banana -> 5
peach -> 300

If you just want pairs just use zip:

for fruit, cost in zip(it,it):
    print("{} -> {}".format(fruit, cost))

banana -> 5
apple -> 400
orange -> 250
peach -> 300

dicts don't have order so that is why the output is in a different order between both.