python *arg, **arg

经常在看一些模块的时候，发现*arg, **arg这样的

查了一下资料

https://pythontips.com/2013/08/04/args-and-kwargs-in-python-explained/

*arg, **arg的区别是*arg为非keyword的字符，而**arg为keyword字符

举个例子

1. >>> def test_var_args(f_arg, *argv):
2. ...     print "first normal arg:", f_arg
3. ...     for pos, arg in enumerate(argv):
4. ...         print "another arg through {0} in {1}:".format(arg, pos)
5. ... 
6. >>> test_var_args('yasoob','python','eggs','test')
7. first normal arg: yasoob
8. another arg through python in 0:
9. another arg through eggs in 1:
10. another arg through test in 2:

 

1. def test_var_args(f_arg, **argv):
2. print "first normal arg:", f_arg
3. for pos, arg in argv.iteritems():
4. print "another arg through {0} in {1}:".format(arg, pos)
5.  
6.  
7. >>> test_var_args('aa', name='python')
8. first normal arg: aa
9. another arg through python in name:
10.  
11. >>> kwargs = {"arg3": 3, "arg2": "two","arg1":5}
12. >>> test_var_args('aa', **kwargs)
13. first normal arg: aa
14. another arg through 5 in arg1:
15. another arg through two in arg2:
16. another arg through 3 in arg3: