Summary of python dynamic loading methods and python Dynamic Loading

Summary of python dynamic loading methods and python Dynamic Loading

This example summarizes the python dynamic package loading method. We will share this with you for your reference. The details are as follows:

Three methods are available for Dynamic Loading modules.

1. Use System Function _ import _()

stringmodule = __import__('string')

2. Use the imp Module

import imp stringmodule = imp.load_module('string',*imp.find_module('string'))imp.load_source("TYACMgrHandler_"+app.upper(), filepath)

3. Use exec

import_string = "import string as stringmodule"exec import_string

Whether the variable exists

1. hasattr (Test, 'T ')
2. 'var 'in locals (). keys ()
3. 'var' in dir ()
4. vars (). has_key ('s ')

Dynamically add attributes

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 Package loading:

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:dyn=Dynload('util.common',['*'])ins=dyn.getClassInstance('C','gao')dyn.execMethod(ins,'test')dyn.execfunc('test','Hello','function!')

Load a specified file by name

Def loadapp (self, app): filepath = "mgr/" + app + ". py "if OS. path. exists (filepath): imp. load_source ("TYACMgrHandler _" + app. upper (), filepath) // modified the app. py: Call this function again, and the new Code will automatically take effect.

Call the corresponding method by name

return getattr(self, op)(args.get("port"), args) //op="start" args=dictgetattr(self, self.request.method.lower())(*args, **kwargs)