Python打印Unicode字符

Question

I'm making a card game, but I've run into what seems to be an encoding issue. I'm trying to print a card like this:

def print(self):
    print("|-------|")
    print("| %s     |" % self.value)
    print("|       |")
    print("|   %s   |" % self.suit.encode("utf-8"))
    print("|       |")
    print("|    %s  |" % self.value)
    print("|-------|")

This is what I want:

|-------|
| 10    |
|       |
|   ♦   |
|       |
|    10 |
|-------|

...but this is what I get:

|-------|
| 10    |
|       |
|   b'\xe2\x99\xa6'   |
|       |
|    10 |
|-------|

I'm on Windows and Python 3 if that matters.

The value of self.suit can be any of the following:

spade = "♠"
heart = "♥"
diamond = "♦"
club = "♣"

If I remove the .encode("utf-8") I get this error:

Traceback (most recent call last):

  File "main.py", line 79, in <module>
    start()
  File "main.py", line 52, in start
    play()
  File "main.py", line 64, in play
    card.print()
  File "main.py", line 36, in print
    print("|   \u2660   |")
  File "C:\Python34\lib\encodings\cp850.py", line 19, in encode
    return codecs.charmap_encode(input,self.errors,encoding_map)[0]
UnicodeEncodeError: 'charmap' codec can't encode character '\u2660' in position
4: character maps to <undefined>

Answer 1

This takes advantage of the fact that the OEM code pages in the Windows console print some visible characters for control characters. The card suits for cp437 and cp850 are chr(3)-chr(6) . Python 3 (prior to 3.6) won't print the Unicode character for a black diamond, but it's what you get for U+0004:

>>> print('\N{BLACK DIAMOND SUIT}')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python33\lib\encodings\cp437.py", line 19, in encode
    return codecs.charmap_encode(input,self.errors,encoding_map)[0]
UnicodeEncodeError: 'charmap' codec can't encode character '\u2666' in position 0: character maps to <undefined>
>>> print(chr(4))
♦

Therefore:

#!python3
#coding: utf8
class Card:
    def __init__(self,value,suit):
        self.value = value
        self.suit = suit    # 1,2,3,4 = ♥♦♣♠

    def print(self):
        print("┌───────┐")
        print("| {:<2}    |".format(self.value))
        print("|       |")
        print("|   {}   |".format(chr(self.suit+2)))
        print("|       |")
        print("|    {:>2} |".format(self.value))
        print("└───────┘") 

Output:

>>> x=Card('K',4)
>>> x.print()
┌───────┐
| K     |
|       |
|   ♠   |
|       |
|     K |
└───────┘
>>> x=Card(10,3)
>>> x.print()
┌───────┐
| 10    |
|       |
|   ♣   |
|       |
|    10 |
└───────┘

Python 3.6 Update

Python 3.6 uses Windows Unicode APIs to print so no need for the control character trick now, and the new format strings can be used:

#!python3.6
#coding: utf8
class Card:
    def __init__(self,value,suit):
        self.value = value
        self.suit = '♥♦♣♠'[suit-1] # 1,2,3,4 = ♥♦♣♠

    def print(self):
        print('┌───────┐')
        print(f'| {self.value:<2}    |')
        print('|       |')
        print(f'|   {self.suit}   |')
        print('|       |')
        print(f'|    {self.value:>2} |')
        print('└───────┘') 

Output:

>>> x=Card('10',3)
>>> x.print()
┌───────┐
| 10    |
|       |
|   ♣   |
|       |
|    10 |
└───────┘