First lesson of python

标签：python   false   

1.    assigment  operator

a=1

a+=1    equal     a=a+1

2.    Conditional operator

‘‘==‘‘ doesn‘t mean ‘‘=‘‘

e.g.      a=1

            b=2

            bool(a==b) => false

3.    if...else

       if []:      if "":      # false 

        if (condition expression1):

        ...

        elif (condition expression2):

        ...

        elif (condition expression3):

        ...

        else:

        ...

4. Question. Why there is no "CASE" in python.

    Answer:   Due to  dict

e.g. 

def    fun1():

                print (‘a‘)

del    fun2():

                print (‘b‘)

del    fun3():

                print (‘c‘)

dict={‘1‘:fun1,‘2‘:fun2,‘3‘:fun3}

dict[‘1‘]()    #d[x] (arguments)

def add(x,y):

    return x+y

...

def f()

        ....

f # function name

f() # execute function

if __name__ = ‘__main__‘ # main function

userdict = {}

user, pw=userinfo.strip().split(‘,‘)

userdict[user]=pw

a=open(‘x.txt‘,‘a‘)

a.write (‘\n%s‘%(name))

a.close()

First lesson of python

标签：python   false   

原文地址：http://luluuy.blog.51cto.com/279347/1791515