python - 构建所选特征的字典

Question

我有 20K 个对象和列表中提供的一组功能。我需要从每个对象中提取这些特征并将它们保存到字典中。每个对象都有近 100 个特征。

例如:

# object1
Object1.Age = '20'
Object1.Gender = 'Female'
Object1.DOB = '03/05/1997'
Object1.Weight = '130lb'
Object1.Height = '5.5'

#object2
Object1.Age = '22'
Object1.Gender = 'Male'
Object1.DOB = '03/05/1995'
Object1.Weight = '145lb'
Object1.Height = '5.8'

#object3
Object1.Age = '22'
Object1.Gender = 'Male'
Object1.DOB = '03/05/1995'
Object1.Weight = '145lb'

#object4
...

以及我需要从每个对象中提取的功能列表(此列表可能会更改，因此我需要代码对此保持灵活):

features = ['Gender', 
        'DOB', 
        'Height']

目前，我正在使用此函数来捕获每个对象所需的所有功能:

def get_features(obj, features):
return {f: getattr(obj, f) for f in features}

如果所有对象都具有我想要的所有功能，则此功能可以完美运行。但有些对象并不具备所有功能。例如，object3 没有名为“Height”的字段。如何将 NaN 作为字典中丢失文件的值，以便防止出现错误？

Answer 1

Python getattr documentation:

getattr(object, name[, default]) Return the value of the named attribute of object. name must be a string. If the string is the name of one of the object’s attributes, the result is the value of that attribute. For example, getattr(x, 'foobar') is equivalent to x.foobar. If the named attribute does not exist, default is returned if provided, otherwise AttributeError is raised.

你可以这样做:

def get_features(obj, features):
    return {f: getattr(obj, f, float('Nan')) for f in features}