Python3 hasattr (), GetAttr (), SetAttr (), delattr () functions, and sample code

This article through the sample code to give you a detailed introduction of Python3 in Hasattr (), GetAttr (), SetAttr (), delattr () function, very good, with reference value, need to refer to a friend

Hasattr () function

The Hasattr () function is used to determine if a corresponding property is included

Grammar:

hasattr(object,name)

Parameters:

object--Object

name--String, property name

return value:

Returns True if the object has this property, otherwise false

Example:

class people:  country= ' China '  def __init__ (self,name):    self.name=name  def people_info (self):    Print ('%s is xxx '% (self.name)) obj=people (' AAA ') print (hasattr (people, ' country ') ") #返回值: Trueprint (' Country ' in people. __dict__) #返回值: Trueprint (hasattr (obj, ' people_info ')) #返回值: Trueprint (people.__dict__) ##{' __module__ ': ' __main__ ', ' Country ': ' China ', ' __init__ ': <function people.__init__ at 0x1006d5620>, ' People_info ': <function People.people_info at 0x10205d1e0>, ' __dict__ ': <attribute ' __dict__ ' of ' people ' objects>, ' __weakref__ ': < Attribute ' __weakref__ ' of ' people ' objects>, ' __doc__ ': None}

GetAttr () function

Describe:

The GetAttr () function is used to return an object property value

Grammar:

getattr(object,name,default)

Parameters:

object--Object

name--strings, Object properties

default--The default return value, if not supplied, Attributeerror is triggered when no property is available.

return value:

Return object property values

class people:  country= ' China '  def __init__ (self,name):    self.name=name  def people_info (self):    Print ('%s is xxx '% (self.name)) obj=getattr (People, ' country ') print (obj) #返回值China #obj=getattr (People, ' Countryaaaaaa ') #print (obj) #报错 # File "/getattr () function. py", line +, in <module>#   obj=getattr (People, ' Countryaaaaaa ') # Attributeerror:type object ' People ' has no attribute ' countryaaaaaa ' obj=getattr (People, ' Countryaaaaaa ', None) print (obj) #返回值None

SetAttr () function

Describe:

The SetAttr function, which is used to set the property value, must exist

Grammar:

setattr(object,name,value)

Parameters:

object--Object

name--strings, Object properties

value--Property value

return value:

No

class people:  country= ' China '  def __init__ (self,name):    self.name=name  def people_info (self):    Print ('%s is xxx '% (self.name)) obj=people (' AAA ') setattr (People, ' X ', 111) #等同于People. X=111print (people.x) #obj. age= 18setattr (obj, ' age ', +) print (obj.__dict__) #{' name ': ' AAA ', ' Age ': 18}print (people.__dict__) #{' __module__ ': ' __main __ ', ' Country ': ' China ', ' __init__ ': <function people.__init__ at 0x1007d5620>, ' people_info ': <function People . People_info at 0x10215d1e0>, ' __dict__ ': <attribute ' __dict__ ' of ' people ' objects>, ' __weakref__ ': < Attribute ' __weakref__ ' of ' people ' objects>, ' __doc__ ': None, ' x ': 111}

Delattr () function

Describe:

The DELATTR function is used to delete properties

Delattr (x, ' Foobar) equals del X.foobar

Grammar:

setattr(object,name)

Parameters:

object--Object

name--must be an object's property

return value:

No

Example:

class people:  country= ' China '  def __init__ (self,name):    self.name=name  def people_info (self):    Print ('%s is xxx '% (self.name)) delattr (People, ' country ') #等同于del People.countryprint (people.__dict__) {' __module__ ': ' __main__ ', ' __init__ ': <function people.__init__ at 0x1006d5620>, ' people_info ': <function People.people_ info at 0x10073d1e0>, ' __dict__ ': <attribute ' __dict__ ' of ' people ' objects>, ' __weakref__ ': <attribute ' __we akref__ ' of ' people ' objects>, ' __doc__ ': None}

Additional examples:

Class Foo:  def run (self):    while True:      cmd=input (' cmd>>: '). Strip ()      if Hasattr (self,cmd):        Func=getattr (Self,cmd)        func ()  def download (self):    print (' Download ... ')  def upload (self):    Print (' Upload ... ') # Obj=foo () # Obj.run ()