[英]How do I use raw_input with classes in a definition
我正在Python 2.7中编写一个脚本,让用户输入元素的原子符号。 然后,脚本将打印出有关元素的信息。
但是,我不确定如何让类使用raw_input
的变量。 以下是具有118个元素以提高可读性的代码:
class PTable(object):
def __init__(self, name, atom_num, atom_sym, atom_mass,period, group, atom_type,state):
self.name = name
self.atom_num = atom_num
self.atom_sym = atom_sym
self.atom_mass = atom_mass
self.period = period
self.group = group
self.atom_type = atom_type
self.state = state
h = PTable("Hydrogen",1,"H",1.0079,1,1,"Nonmetal","Gas")
he = PTable("Helium",2,"He",4.0026,1,18,"Nonmetal","Gas")
li = PTable("Lithium",3,"Li",6.941,2,1,"Alkali metal","Solid")
be = PTable("Beryllium",4,"Be",9.0121831,2,2,"Alkaline earth","solid")
og = PTable("Oganesson",1,"H",1.008,1,1,"Nonmetal","Gas")
def results(name, num, sym, mass, per, gro, typ, state):
print "Name:", name
print "Atomic number:", num
print "Atomic symbol:", sym
print "Atomic mass:", mass
print "Period:", per
print "Group:", gro
print "Type:", typ
print "State:", state
# results(h.name, h.atom_num, h.atom_sym, h.atom_mass, h.period, h.group, h.atom_type, h.state)
def hub():
x = raw_input("What element? ")
results(%s.name, %s.atom_num, %s.atom_sym, %s.atom_mass, %s.period, %s.group, %s.atom_type, %s.state) % (x)
hub()
hub()
给我语法错误的代码是:
results(%s.name, %s.atom_num, %s.atom_sym, %s.atom_mass, %s.period, %s.group, %s.atom_type, %s.state) % (x)
错误很明显; 语法是错误的,所以我尝试了另一种方法:
results(x.name, x.atom_num, x.atom_sym, x.atom_mass, x.period, x.group, x.atom_type, x.state)
那也行不通,我得到了错误
追溯(最近一次通话):
文件“ C:/Users/NAME/Desktop/PTable.py”,行146,位于
hub()
集线器中的文件“ C:/Users/NAME/Desktop/PTable.py”,第143行
results(x.name, x.atom_num, x.atom_sym, x.atom_mass, x.period, x.group, x.atom_type, x.state)
AttributeError:“ str”对象没有属性“ name”
您知道我该怎么做,以便用户能够键入元素的名称(原子符号),然后代码将信息打印出来?
x = raw_input("What element? ")
您提供了一个字符串,说'he'
,因此,当您调用x.name
您尝试访问的是该字符串的属性,而不是变量he
的属性。
您应该做的是将元素存储在字典中,而不是将它们作为变量并使用用户提供的键来访问它们。
periodic_table = {
'h': PTable("Hydrogen",1,"H",1.0079,1,1,"Nonmetal","Gas"),
'he': PTable("Helium",2,"He",4.0026,1,18,"Nonmetal","Gas"),
...
}
symbol = raw_input("What element? ")
try:
element = periodic_table[symbol]
except KeyError:
print('This element does not exist')
至于打印元素,我将通过实现PTable.__str__
方法来建议一种更加面向对象的方法。
class PTable(object):
...
def __str__(self):
# Add in the format and information that you want to be printed
return "Name: {}".format(self.name)
然后,您可以直接打印您的元素。
print periodic_table['he']
# prints: 'Name: Helium'
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