how to find the same element in list of tuple and substitute it in Python?

Question

I have a list of tuple like this:

 t= [('A', 3000, '20140304'), ('B', 2000, '20140304'),('DD',3000, '20140304'), ('N', 102, '20140305'), ('S', 136, '20140305'), ('N', 182, '20140305'),('G',136, '20140305')]

I want to find if it has a same price on same date. If it does, return a new list of tuple pair with the name.The output should like this:

[('A','DD'),('S','G')]

Well then start with writing some code. – Ashwini Chaudhary Aug 03 '15 at 21:44 — Ashwini Chaudhary, Aug 03 '15 at 21:44
I tried using index and loop but doesn't work – Toffee H Aug 03 '15 at 21:54 — Toffee H, Aug 03 '15 at 21:54

score 0 · Answer 1 · answered Aug 03 '15 at 21:51

import collections as coll

t = [('A', 3000, '20140304'), ('B', 2000, '20140304'),('DD',3000, '20140304'), ('N', 102, '20140305'), ('S', 136, '20140305'), ('N', 182, '20140305'),('G',136, '20140305')]

d = coll.defaultdict(lambda:coll.defaultdict(set))
for a,p,stackOverflow in t: d[stackOverflow][p].add(a)

for t in d:
    for p in d[t]:
        print("On day", t, ", the following items were sold at price", p, ':\n' + ','.join(sorted(d[t][p])))

score 0 · Accepted Answer · edited May 23 '17 at 11:48

0

You can aggregate the tuples into a defaultdict with a tuple of (price, date) as the key. Iterate through that defaultdict, and return any list of names with more than one item.

from collections import defaultdict

price_date_dict = defaultdict(list)

for name, price, date in t:
    price_date_dict[(price, date)].append(name)

return [tuple(names) for names in price_date_dict.values() if len(names) > 1]

edited May 23 '17 at 11:48

Community

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answered Aug 03 '15 at 21:52

horns

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I think a `price_date_dict.items()` is needed – JuniorCompressor Aug 03 '15 at 21:56
@JuniorCompressor Yes, that was incorrect. Thank you. – horns Aug 03 '15 at 22:04

how to find the same element in list of tuple and substitute it in Python?

2 Answers2