如何检查列表中具有特定要求的所有元素？

Question

I'm doing a homework about a heart game with different version. It says that if we are given a list mycards that contains all the cards that player currently hold in their hands. And play is a single card that representing a potential card.And if all their cards contain either HEART( H ) or QUEEN OF SPADES( QS ) it is going to return True.

For example

>>> mycards= ['0H','8H','7H','6H','AH','QS']
>>> play = ['QS']

It will return True

this is what I have tried

if play[1] == 'H':
    return True
if play == 'QS':
    return True
else:
    return False

But I think my codes just check one QS and one H in the list. How to make the codes that contain all either QS or H?

Answer 1

Your description maps directly to the solution:

Edited for clarity:

mycards= ['0H','8H','7H','6H','AH','QS'] 
all((x == 'QS' or 'H' in x) for x in mycards)
#  True

Answer 2

>>> mycards= ['0H','8H','7H','6H','AH','QS']
>>> all(x[-1] == 'H' or x == 'QS' for x in mycards)
True

Answer 3

Since its your 'Homework' I'm not going to provide you with ready-made code. :)

Iterate over the list using a loop:

for eg.:

for el in mycards:

at each iteration you have to check either any of the two conditions are true or not.

if el == 'QS' or el[1] == 'H':

if card is either Queen of Spade or a Heart above condition will be true. Hope you get it till now. And if the condition is not true, simply return False.

If all the elements in your lists are checked by the loop and yet no False returned, hence the all cards are either Queen of Spade or a Heart. So return True after the loop ends.

Try on your own for a while, if still not getting I'll post the code at your request (but you'll have to show me what you tried :p)

Edit: Since you've tried it, I'm posting code too.

def HorQS(mycards):
    for i in mycards:
        if i != 'QS':
            if i[1] != 'H':
                return False
    return True

print HorQS(['0H','8H','7H','6H','AH','QS'])  # True
print HorQS(['0H','8H','7H','6H','AH','HS'])  # False
print HorQS(['0H','8H','7K','6H','AH','HS'])  # False