Can I convert a string to arguments list in python?
def func(**args):
for a in args:
print a, args[a]
func(a=2, b=3)
# I want the following work like above code
s='a=2, b=3'
func(s)
I know:
list can, just use *list, but list can't have an element like: a=2
and eval can only evaluate expression
which would be like:
def func2(*args):
for a in args:
print a
list1=[1,2,3]
func2(*list1)
func2(*eval('1,2,3'))
You could massage the input string into a dictionary and then call your function with that, e.g.
>>> x='a=2, b=3'
>>> args = dict(e.split('=') for e in x.split(', '))
>>> f(**args)
a 2
b 3
tuple(e.split('=')) for e in x.split(', ') will cause syntax error, isn't it an argument of dict()? Is there an explain about this rule?
int to all values, e.g. args = {k: int(v) for k, v in args.items()}You want a dictionary, not an 'argument list'. You also would be better off using ast.literal_eval() to evaluate just Python literals:
from ast import literal_eval
params = "{'a': 2, 'b': 3}"
func(**literal_eval(params))
Before you go this route, make sure you've explored other options for marshalling options first, such as argparse for command-line options, or JSON for network or file-based transfer or persistence.
a=2, b=3 string is user input (e.g. from a configuration file or the like); you'd rather not allow evaluating arbitrary Python code. :-}
args "(1, 2, 3)" and func2(*literal_eval(args)) here; e.g. something that would produce the right python structure to apply to call.You can use the string as an argument list directly in an call to eval, e.g.
def func(**args):
for a in args:
print( a, args[a])
s = 'a=2, b=3'
eval('func(' + s + ')')
>>>b 3
>>>a 2
Note that func needs to be in the namespace for the eval call to work like this.
parse_args()with arguments.