CODEWITHSUNDEEP
python-3.x
Ruben Fontes
Ruben Fontes

Reputation: 13

Trying to make this work with two characters and not just one

def main():
    result = ""
    cards = ["2","3","5","5","J"]
    previous = cards[0]
    current = cards[1]

    i = 1
    while i < len(cards) and result == "" :

        previous = cards[i - 1]
        current = cards[i]

        if current == previous:
            result = result + current
            result = result + previous
        i = i + 1

    print(result)

main()

#Need this to work with 2 characters as in instead of the number list i would like ["2D","3C","5H","5D","JS"], But I'm not sure how to do it...

Upvotes: 1

Views: 66

Answers (3)

erip
erip

Reputation: 16935

Here's a more Pythonic solution which uses itertools:

test.py

from itertools import tee

def pairwise(iterable):
    "s -> (s0,s1), (s1,s2), (s2, s3), ..."
    a, b = tee(iterable)
    next(b, None)
    return zip(a, b)

def main():
    result = ""
    cards = ["2D","3C","5H","5D","JS"]

    # Generate adjacent pairs
    for prev, curr in pairwise(cards):
      # Append `prev` to `curr` if the first character is the same.
      if prev[0] == curr[0]:
        result = curr + prev

    print(result)

if __name__ == "__main__":
    main()

The function pairwise will take an iterable, s = ["s0", "s1", "s2", "s3"], which can be iterated over by two elements that are adjacent. That said, you can look at the "current" and the "next" or the "previous" and the "current". I chose prev and curr because next is a keyword in Python (see its use in pairwise, actually).

You can do something like

for prev, curr in pairwise(s):
  print("prev: {}, curr: {}".format(prev, curr))

This would print:

prev: s0, curr: s1
prev: s1, curr: s2
prev: s2, curr: s3

You can then check the first element of each string with string indexing.

07:35 $ python3 test.py 
5H5D

Upvotes: 0

Steven Summers
Steven Summers

Reputation: 5384

String objects support indexing. For example

string = 'ABC123'
string[0]   | 'A'
string[-1]  | '3'
string[0:3] | 'ABC'

So by using if current[0] == previous[0]: you are checking the first value of the strings.

def main():
    result = ""
    cards = ["2D","3C","5H","5D","JS"]
    previous = cards[0]
    current = cards[1]

    i = 1
    while i < len(cards) and result == "":

        previous = cards[i-1]
        current = cards[i]

        if current[0] == previous[0]:
            result = previous + current

        i = i + 1

    print(result)

main()

Upvotes: 1

Tales P&#225;dua
Tales P&#225;dua

Reputation: 1461

In the line previous = [i-1] you forgot to put the cards[i-1]

If you want to put the two digits, but compare only the number of your cards, you can just compare the first char of the string:

if current[0] == previous[0]:
    result = result + current
    result = result + previous

This printed to me 5D5H

Upvotes: 1

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