我想打印一个特定的Python字典键:
mydic = {}
mydic['key_name'] = 'value_name'
现在我可以检查mydic.has_key('key_name'),但我想做的是打印密钥'key_name'的名称。当然,我可以使用mydic.items(),但我不希望列出所有的键,而只是一个特定的键。例如,我期望这样的东西(在伪代码中):
print "the key name is", mydic['key_name'].name_the_key(), "and its value is", mydic['key_name']
是否有name_the_key()方法打印键名?
编辑:
好的,非常感谢大家的反应!:)我意识到我的问题没有很好地表达出来,而且很琐碎。我只是感到困惑,因为我意识到'key_name'和mydic['key_name']是两个不同的东西,我认为将'key_name'打印出字典上下文是不正确的。但实际上,我可以简单地使用“key_name”来引用键!:)
根据定义,字典有任意数量的键。没有“钥匙”。你有keys()方法,它给你一个包含所有键的python列表,还有iteritems()方法,它返回键值对,所以
for key, value in mydic.iteritems() :
print key, value
Python 3版本:
for key, value in mydic.items() :
print (key, value)
所以你可以处理键,但它们只有在与值耦合时才有意义。我希望我已经理解了你的问题。
在Python 3中:
# A simple dictionary
x = {'X':"yes", 'Y':"no", 'Z':"ok"}
# To print a specific key (for example key at index 1)
print([key for key in x.keys()][1])
# To print a specific value (for example value at index 1)
print([value for value in x.values()][1])
# To print a pair of a key with its value (for example pair at index 2)
print(([key for key in x.keys()][2], [value for value in x.values()][2]))
# To print a key and a different value (for example key at index 0 and value at index 1)
print(([key for key in x.keys()][0], [value for value in x.values()][1]))
# To print all keys and values concatenated together
print(''.join(str(key) + '' + str(value) for key, value in x.items()))
# To print all keys and values separated by commas
print(', '.join(str(key) + ', ' + str(value) for key, value in x.items()))
# To print all pairs of (key, value) one at a time
for e in range(len(x)):
print(([key for key in x.keys()][e], [value for value in x.values()][e]))
# To print all pairs (key, value) in a tuple
print(tuple(([key for key in x.keys()][i], [value for value in x.values()][i]) for i in range(len(x))))