In python how to count occurance of elements in list

Question

I have the following list;

['html', 'header', 'title', 'body', 'div', 'div', 'div', 'div', 'div', 'ul', 'li', 'li', 'li']

i want to print items having occurrence three or more.

output should be 'li' and 'div'

Can anyone help me python code to do this.

[`collections.Counter`](https://docs.python.org/2/library/collections.html#collections.Counter) — moooeeeep, Jan 10 '15 at 12:30
Counting the occurance of an element is a duplicate of http://stackoverflow.com/questions/2600191/how-can-i-count-the-occurrences-of-a-list-item-in-python. The rest is basic logic. — Reti43, Jan 10 '15 at 12:30

score 1 · Accepted Answer · answered Jan 10 '15 at 12:32

1

Try this:

>>> from collections import Counter

>>> l = ['html', 'header', 'title', 'body', 'div', 'div', 'div', 'div', 'div', 'ul', 'li', 'li', 'li']
>>> [item for item, cnt in Counter(l).items() if cnt > 2]
['li', 'div']

answered Jan 10 '15 at 12:32

elyase

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score 1 · Answer 2 · answered Jan 10 '15 at 12:34

1

Without using Counter,

In [198]: e = ['html', 'header', 'title', 'body', 'div', 'div', 'div', 'div', 'div', 'ul', 'li', 'li', 'li']
In [199]: list(set([v for v in e if e.count(v)>=3]))
Out[199]: ['li', 'div']

(Only for short lists as it isn't too efficient).

answered Jan 10 '15 at 12:34

xnx

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its better to use set for `e` : `>>> [v for v in set(e) if e.count(v)>=3] ['li', 'div']` – Mazdak Jan 10 '15 at 12:38
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@xnx, this is quadratic as opposed to a linear solution using Counter – Padraic Cunningham Jan 10 '15 at 12:41
@Padraic Cunningham. True, as noted in my answer. Whether this makes a difference in practice depends on the length of the tag list, though. – xnx Jan 10 '15 at 13:16

Vivek Sable · Answer 3 · 2015-01-10T12:41:11.203

Use collections module.

Counter method will add all items from list l as key and value is their counts. So you can find keys according their counts by your logic.

Code:

from collections import Counter

l = ['html', 'header', 'title', 'body', 'div', 'div', 'div', 'div', 'div', 'ul', 'li', 'li', 'li']

c = Counter(l)
for key, count in c.items():
    print("[{}] - {}".format(key, count))

Output:

[body] - 1
[ul] - 1
[title] - 1
[li] - 3
[header] - 1
[html] - 1
[div] - 5

Documentation for this module https://docs.python.org/2/library/collections.html

score 0 · Answer 4 · edited Jan 10 '15 at 15:48

0

L = ['html', 'header', 'title', 'body', 'div', 'div', 'div', 'div', 'div', 'ul', 'li', 'li', 'li']

result = []

for i in range(len(L)):

    if L.count(L[i]) >= 3 and L[i] not in result:
        result.append(L[i])

print result

Output

['div', 'li']

edited Jan 10 '15 at 15:48

Reti43

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answered Jan 10 '15 at 14:33

hariK

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In python how to count occurance of elements in list

4 Answers4