First clear solution for How to Find Friends by gyahun_dash - python coding challenges

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First solution in Clear category for How to Find Friends by gyahun_dash

from itertools import chain

def check_connection(shakehands, me, you):
    hands = {tuple(pair.split('-')) for pair in shakehands}
    amigos = {me}

    while amigos != set():
        pairs = {pair for pair in hands if any(one in pair for one in amigos)}
        amigos = set(chain(*pairs)) - amigos
        if you in amigos: return True
        hands -= pairs

    return False

June 4, 2014

Comments:

teplolog on June 12, 2014, 5:26 p.m.
Code looks like a story!

gyahun_dash on June 12, 2014, 6:37 p.m.
I believe they(you and I) are friends (but sometimes not).

Cjkjvfnby on Aug. 5, 2014, 10:51 p.m.
<a href="http://www.checkio.org/forum/post/1618/proper-way-to-check-if-sequence-is-empty/">http://www.checkio.org/forum/post/1618/proper-way-to-check-if-sequence-is-empty/</a>

gyahun_dash on Aug. 6, 2014, 3:17 p.m.
Thank you.

Peter.White on April 7, 2015, 11:39 a.m.
I had to giggle a little while reading the code. ;) Very nice.

Jemmity on April 28, 2015, 9:48 p.m.
Like a wave spreading across the network. Top stuff!

shenwsshen on May 11, 2015, 6:39 a.m.
it a bit difficult for me ,but it looks very cool

rajsharmabannu on May 27, 2015, 4:25 p.m.
Knew that i had to use sets but then didn't know how to exactly use them :/ This one taught me something atleast. Thanks nice code. :)

mlb00 on July 21, 2015, 11:52 p.m.
Could someone please walk me through the while loop? Thanks!

aslanseyes on Aug. 21, 2015, 3:03 a.m.
Others please correct if I'm wrong, but here's my take! line 7: loop while amigos is not empty (although note the PEP8 advice above) line 8: pairs keeps only the name pairs that include a name from the amigos set line 9: creates a union of all the pairs from previous line and then removes all of the names from the current amigos set (i.e., now we have a set of all the partners of the amigos) line 10: if the second name is in the set of partners, return True (because we've created a link of names that can be traced in pairs back to the first name) line 11: remove all the line 8 pairs from the remaining network of pairs, because they've been accounted for line 13: if we account for every pair in the original network that is connected to the first name, then amigos is empty, and the loop finishes, returning False.

dientu on Sept. 27, 2015, 1:40 p.m.
Hi @gyahun_dash , This is good approach to solve this problem. Just would like to improve my Python knowledge, could you please explain: Question #1: why use <pre class='brush: python'>{tuple (pair.split('-')).....} </pre> And, other concerns: I see if I remove "tuple", the program will return error "unhashable type: 'list'" --> why ??? Or, I try to change code to (tuple (pair.split('-').....). The program returns computer memory ID --> why ???? Question #2: <pre class='brush: python'>amigos = set(chain(*pairs)) - amigos </pre> so we can use the minus " - " to remove element between lists ??? could you please send me the document to read ? Thanks, @dientu

Franky on Dec. 12, 2015, 2:10 p.m.
I just got the it and can answer you. for question #1: if no tuple, (pair.split('-')) returns a list though it has parenthesis around. that's where should use tuple() constructor. for question #2: - is not intended to remove element between lists. while it is used just for sets. you can use minus to get a difference of two sets. refer to sets for more detail.<a href="https://docs.python.org/2/library/stdtypes.html#set-types-set-frozenset">document for set</a>

chchun on Sept. 12, 2018, 4:20 a.m.
chain? look nice!!!

Marcin_Ramotowski on July 3, 2021, 10:29 a.m.
Nice code :)

Vasya07 on Nov. 14, 2021, 3:06 p.m.
Funny and creative solution.) Chain from itertools is a new method for me, thanks for a chance to learn.

jsg-inet on Nov. 24, 2021, 9:11 a.m.
It takes me time to understand the "philosophy" of the algorithm, but now I think I understand it. Wow! I have learn a lot with this code! Thank you!

viktor.chyrkin on Feb. 6, 2022, 12:42 a.m.
amigos! blah blah blah! Nice code! I never thought tat a programists name is amigo! XD

m.kurapov on Feb. 12, 2023, 7:52 p.m.
Funny and creative solution.) Chain from itertools is a new method for me, thanks for a chance to learn.

Pactp on Jan. 5, 2024, 10:18 a.m.
Nice solution. Clear names and clear set handling. Thank you

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