CODEWITHSUNDEEP
python
Kev Mü
Kev Mü

Reputation: 13

compare string to list elements python

i need some help to solve my problem with python. My task is to generate 4 Elements of my list "stones", which i want to put in my List "L". The letters are colours and +,-,.. are forms and i'm allowed to just use every colour and form one time in my 4 Elements, which is why i struggle with this task. my code so far:

L = []
stones = ["R+", "R-", "R*", "R_", "G+", "G-", "G*", "G_", "B+",  "B-", "B*", "B_", "W+", "W-", "W*", "W_"]
stone1 = random.choice(stones) 
L.append(stone1)
stones.remove(stone1)
#if stone1[1] in stones:
#del stones

as you can hopefully see, i get a random value of "stones" and can put it in my list L and i delete it out of the stones list. The problem now is that i dont know how to compare stone1 to the other stones.elements. f.e. if i get stone1=R+, i want to delete all items in "stones" which include R and +. The last 2 lines are garbage, so don't worry.. Thanks for your help!

Upvotes: 0

Views: 322

Answers (7)

mugabits
mugabits

Reputation: 1035

You saved the value to compare as stone1.

You could separate into two strings where string1 is the first character and string2 is the second character. Then use 1 loop and compare each item to the two strings/characters you're interested on ("R", +" in your example), and for each match remove the item from the list.

Also, use the least number of comparisons needed and one loop/pass. For example, if you found a match, then remove item and continue with the loop avoiding a second comparison. 

L = []
stones = ["R+", "R-", "R*", "R_", "G+", "G-", "G*", "G_", "B+",  "B-", "B*",    "B_", "W+", "W-", "W*", "W_"]
stone1 = random.choice(stones) 
L.append(stone1)
stones.remove(stone1)

foo1 = stone1[0]
foo2 = stone1[1]      

for x in stones:
  if x.startswith(foo1):
    stones.remove(x)
  elif x.endswith(foo2):
    stones.remove(x)

Upvotes: 0

DisplacedAussie
DisplacedAussie

Reputation: 4704

from itertools import product
from random import sample

# Define your colours and forms (easy to add more later)
colours = ['R', 'G', 'B', 'W']
forms = ['+', '-', '*', '_']

# Combine the colours and forms to show all combinations
possible_stones = [''.join(stone) for stone in product(colours, forms)]
print possible_stones
>>> ['R+', 'R-', 'R*', 'R_', 'G+', 'G-', 'G*', 'G_', 'B+', 'B-', 'B*', 'B_', 'W+', 'W-', 'W*', 'W_']

# Get a random sample of the forms and colours and then combine them
stones = zip(sample(colours, len(colours)), sample(forms, len(forms)))
print [''.join(stone) for stone in stones]
>>> ['B+', 'G*', 'R-', 'W_']

Upvotes: 0

Mark Tolonen
Mark Tolonen

Reputation: 178334

Since you can have one of each color and form, just shuffle them separately. There is no need to have a starting list of every combination:

def get_stones():
    colors = list('RGBW')
    forms = list('+-*_')
    random.shuffle(colors)
    random.shuffle(forms)
    return [c+f for c,f in zip(colors,forms)]

for i in range(5):
    print(get_stones())

Output:

['B*', 'R-', 'W_', 'G+']
['W*', 'R+', 'G_', 'B-']
['B+', 'R_', 'G-', 'W*']
['B+', 'G*', 'W-', 'R_']
['G_', 'B-', 'W*', 'R+']

Note: If order doesn't matter you can drop one of the shuffles.

Upvotes: 3

gipsy
gipsy

Reputation: 3859

stones = filter(lambda x: stone1[0] not in x and stone1[1] not in x, stones)

Tweak the conditional in the filter above to fit your need.

Upvotes: 0

R Nar
R Nar

Reputation: 5515

>>> L = []
>>> stones = ["R+", "R-", "R*", "R_", "G+", "G-", "G*", "G_", "B+",  "B-", "B*", "B_", "W+", "W-", "W*", "W_"]
>>> while stones: #continue until stones is empty since empty lists return False
       stone1 = stones.pop(random.randrange(len(stones))) #pop returns and removes an item from a list
       L.append(stone1)
       stones = [stone for stone in stones if stone1[0] not in stone and stone1[1] not in stone] #list comp that only copies values if neither characters are in the item


>>> L
['W_', 'R+', 'G*', 'B-']

Upvotes: 0

Hadrián
Hadrián

Reputation: 354

You can do it like:

import random
L = []
stones = ["R+", "R-", "R*", "R_", "G+", "G-", "G*", "G_", "B+",  "B-", "B*", "B_", "W+", "W-", "W*", "W_"]
stone1 = random.choice(stones) 
L.append(stone1)
for character in stone1:
    copy_stones=stones[:]  # You need to make a copy, if not the for fails
    for stone in copy_stones:
        if character in stone:
            stones.remove(stone)

Upvotes: 0

ham_string
ham_string

Reputation: 139

If you get your stone, I'd split it in

color = stone1[0]
form = stone1[1]

and then iterate through your stone list and eliminate every stone which contains either coloror form. Continue until len(L) = 4 and you're done.

Upvotes: 0

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