打印密钥名称及其值

Question

我有一个语句，它打印一个字符串，与一种化学物质及其所需的键值有关，如何打印键值对应的键名？你知道吗

def chemByString(chemName,chemicals,priority="echo"):
    for chemical in chemicals:
        chemDict = chemical.toDict(priority)
        if chemDict["chemicalName"] == chemName
            return chemical
    return None

print str(chemByString('O2', allChemicals, priority="echo").chemicalName) + str("{chemicalName:<5s} {charge:<20s}{comment:<20s}".format(**chemByString('O2', allChemicals, priority="echo").toDict()))

输出：

{'tv': 'O2', 'echo': 'O2'} O2     0     O2   

期望输出：

{'tv': 'O2', 'echo': 'O2'} O2 Charge 0 Comment O2

或者

                         Species  Charge   Comment

{'tv': 'O2', 'echo': 'O2'}  O2        0       O2 

Answer 1

可以使用list comprehension中的getattr()使用属性列表打印对象属性：

properties = ('chemicalName', 'speciesName', 'charge', 'comments')
template = '{0:<20s} {1:<5s} {2:<20s} {3:<20s}'

chem = chemByString('O2', allChemicals, priority="echo")

print template.format(*properties)
print template.format(*[str(getattr(chem, p)) for p in properties])