您可以阻止函数在python的字典映射中执行吗？

Question

When mapping functions to a dictionary, python automatically executes the function before the key is called. Can this be prevented? Example:

def testfunc():
    print 'Executed'

testdict = { '1': testfunc(),}
>>>EXECUTED

If not, is there a better way to do this? Would this be a call for decorators or something?

Answer 1

The way you are creating the dictionary maps the return value of testfunc() to the key '1' . In order to know the return value, the function has to be executed first. If you are simply trying to save the function in the dictionary, do:

testdict = {'1': testfunc,}

Answer 2

Simply, remove the parentheses after the function's name when mapping:

testdict = {'1': testfunc,} # remove the parentheses, in order to save the function, 
                            # not its return value

& to call it:

testdict['1']()

Answer 3

Yes, you may prevent the execution pf method, by not calling it,menas by not providing the parentheses. And whenever you want to call the method you can,see below:

def testfunc():
    print 'Executed'
testdict = {'1': testfunc,}
testdict['1']()
Executed