Python : a way to calculate

Question

Is there any way to calculate the counting of names in the list?

The following example is written by using the method of count().

Then, the outcome should be the dictionary as the same output.

Attention: do not use built-in count() method and should return a dictionary. If the list is empty, it will return an empty dictionary.

a=['Mary', 'David','Grace','Curtis','Alice','Joe','Grace']

# use count
print(dict(map(lambda x  : (x , list(a).count(x)) , a)))

output: {'Mary': 1, 'David': 1, 'Grace': 2, 'Curtis': 1, 'Alice': 1, 'Joe': 1}

@Mateen Ulhaq the way you introduce is also using count method. The answer should not use pandas or count. — AAlex, Jun 03 '18 at 04:15
Oh. It's pretty simple to roll your own, no? Just loop over all items. Increment counts depending on the item. https://repl.it/@SicariusNoctis/BreakableAromaticClosedsource — Mateen Ulhaq, Jun 03 '18 at 04:50
@MateenUlhaq ok, you did not use count method. but your answer is defaultdict(, {'Mary': 1, 'David': 1, 'Grace': 2, 'Curtis': 1, 'Alice': 1, 'Joe': 1}). return so many unneccessary words. — AAlex, Jun 03 '18 at 06:32
`print(dict(counts))`. Alternatively, you can get by without using `defaultdict` at all, but it's the recommended style. — Mateen Ulhaq, Jun 03 '18 at 06:36

ThePoetCoder · Answer 1 · 2018-06-03T04:23:59.100

0

from collections import Counter
c = dict(Counter(long_list_with_duplicates))
print(c)

edited Jun 03 '18 at 04:23

answered Jun 03 '18 at 04:09

ThePoetCoder

if do not use counter. The example already uses counter. – AAlex Jun 03 '18 at 04:11
@AAlex your example uses `count()`, not `Counter()`. – RoadRunner Jun 03 '18 at 04:14
not use build-in count() method – AAlex Jun 03 '18 at 04:18
But it doesn't do that. It is using the class Counter, from the collections module instead of the built in count method for lists – ThePoetCoder Jun 03 '18 at 04:20
The outcome should be a dictionary. That will not be a dictionary. – AAlex Jun 03 '18 at 04:22
I've edited the answer now by wrapping the counter in a dict() – ThePoetCoder Jun 03 '18 at 04:24
@AAlex Use a `defaultdict`. `from collections import defaultdict counts = defaultdict(int) for name in a: counts[name] += 1 print(dict(counts))` – RoadRunner Jun 03 '18 at 04:24
if the list is empty, it should return an empty dictionary. – AAlex Jun 03 '18 at 04:31
using counter instead of built-in count() -->strange.(but cannot tell how is strange.) – AAlex Jun 03 '18 at 04:36

1 Answers1