Python dynamic Load Package method detailed description

This article summarizes the Python dynamic Load package method. Share to everyone for your reference, as follows:

There are three ways to load modules dynamically

1. Using the system function __import_ ()

Stringmodule = __import__ (' string ')

2. Using the Imp module

Import Imp stringmodule = Imp.load_module (' String ', *imp.find_module (' string ')) Imp.load_source ("Tyacmgrhandler_" + App.upper (), filepath)

3. Use the Exec

import_string = "Import string as Stringmodule" exec import_string

Whether a variable exists

1. Hasattr (Test, ' t ')
2. ' Var ' in locals (). Keys ()
3. ' Var ' in Dir ()
4. VARs (). Has_key (' s ')

Dynamically increasing properties

Class Obj (object):  passdef Main ():  list=["A", "B", "C"] for  i inrange (1,len (list), 2):    obj = Type (' obj ' , (), {list[i]:lambdaself,s:obj.__setattr__ (s.split ("=") [0],s.split ("=") [1])})  obj =obj () for  I inrange (0, Len (list), 2):    obj.__setattr__ (List[i],list[i])    obj.a =1  obj.b ("a =2")  obj.b ("C =3"  ) PRINTOBJ.A  printobj.cif __name__ = = ' __main__ ':  Main ()

Dynamic Load Package:

def test (s,e):  print s  print Eclass C ():  def __init__ (self,name):    print name  def test (self):    print ' class!!! '

Loader code:

Class Dynload ():  def __init__ (self,package,imp_list):    self.package=package    self.imp=imp_list  def GetObject (self):    return __import__ (Self.package,globals (), locals (), self.imp,-1)  def getclassinstance ( Self,classstr,*args):    return GetAttr (Self.getobject (), Classstr) (*args)    def execfunc (Self,method,*args):    return GetAttr (Self.getobject (), method) (*args)  def execmethod (Self,instance,method,*args):    return GetAttr (Instance,method) (*args) #Test:d yn=dynload (' Util.common ', [' * ']) ins=dyn.getclassinstance (' C ', ' Gao ') Dyn.execmethod (INS, ' Test ') dyn.execfunc (' Test ', ' Hello ', ' function! ')

Load the specified file by name

def Loadapp (self, app):    filepath= "mgr/" +app+ ". Py"    if Os.path.exists (filepath):      Imp.load_source (" Tyacmgrhandler_ "+app.upper (), filepath)//Modify the app.py, call this function from the new code automatically

Call the corresponding method according to the name

Return GetAttr (Self, op) (Args.get ("Port"), args)//op= ' start ' args=dictgetattr (self, Self.request.method.lower ()) (* args, **kwargs)