Python implements structurally similar function call methods

Python dict is very convenient to use, you can customize the key value, and access through subscripts, as shown in the following example:

>>> d = {'key1':'value1',

... 'key2':'value2',

... 'key3':'value3'}

>>> print d['key2']

value2

>>>

Lambda expressions are also useful, for example:

>>> f = lambda x : x**2

>>> print f(2)

4

>>>

The combination of the two can achieve a similar structure of function calls, it is very convenient to use, as follows:

Example 1: no parameters  

#! /usr/bin/python

 

msgCtrl = "1 : pausen2 : stopn3 : restartnother to quitn"

 

ctrlMap = {

'1':    lambda : doPause(),

'2':    lambda : doStop(),

'3':    lambda : doRestart()}

 

def doPause():

        print 'do pause'

 

def doStop():

        print 'do stop'

 

def doRestart():

        print 'do restart'

 

if __name__ == '__main__':

        while True:

                print msgCtrl

                cmdCtrl = raw_input('Input : ')

                if not ctrlMap.has_key(cmdCtrl):break

                ctrlMap[cmdCtrl]()

Example 2: take parameters

#! /usr/bin/python

 

msgCtrl = "1 : +n2 : -n3 : *nother to quitn"

 

ctrlMap = {

'1':    lambda x,y : x+y,

'2':    lambda x,y : x-y,

'3':    lambda x,y : x*y}

 

 

if __name__ == '__main__':

        while True:

                print msgCtrl

                cmdCtrl = raw_input('Input : ')

                if not ctrlMap.has_key(cmdCtrl):break

                print ctrlMap[cmdCtrl](10,2),"n"