sum(x ** 2 for x in xrange(4))

sum([x ** 2 for x in xrange(4)]) 

 #三元表达式

 name='alex'

 name='egon'

 res='SB' if name == 'alex' else 'shuai'

 print(res)

 #例子1

 egg_list=[]

 for i in range(100):

     egg_list.append('egg%s' %i)

 print(egg_list)

 l=['egg%s' %i for i in range(100) if i > 50]

 print(l)

 #例子2

 l=[1,2,3,4]

 s='hello'

 l1=[(num,s1) for num in l if num > 2 for s1 in s]

 print(l1)

 l1=[]

 for num in l:

     for s1 in s:

         t=(num,s1)

         l1.append(t)

 print(l1)

 #例子3

 import os

 g=os.walk('C:\\egon')

 file_path_list=[]

 for i in g:

     # print(i)

     for j in i[-1]:

         file_path_list.append('%s\\%s' %(i[0],j))

 print(file_path_list)

 g=os.walk('C:\\egon')

 l1=['%s\\%s' %(i[0],j) for i in g for j in i[-1]]

 print(l1)

 #例子1

 l=['egg%s' %i for i in range(100)]

 print(l)

 g=l=('egg%s' %i for i in range(10000))

 print(g)

 print(next(g))

 print(next(g))

 for i in g:

     print(i)

 #例子2

 f=open('a.txt')

 l=[]

 for line in f:

     line=line.strip()

     l.append(line)

 print(l)

 f.seek(0)

 l1=[line.strip() for line in f]

 print(l1)

 f.seek(0)

 g=(line.strip() for line in f)

 print(g)

 print(next(g))

 #例子3

 f=open('a.txt')

 g=(line.strip() for line in f)

 l=list(g)

 print(l)

 nums_g=(i for i in range(3))

 # print(sum([1,2,3,4]))

 print(sum(nums_g))

 #例子4

 money_l=[]

 with open('b.txt') as f:

     for line in f:

         goods=line.split()

         res=float(goods[-1])*float(goods[-2])

         money_l.append(res)

 print(money_l)

 f=open('b.txt')

 g=(float(line.split()[-1])*float(line.split()[-2]) for line in f)

 print(sum(g))

 with open('b.txt') as f:

     print(sum((float(line.split()[-1])*float(line.split()[-2]) for line in f)))

 #例子5

 res=[]

 with open('b.txt') as f:

     for line in f:

         # print(line)

         l=line.split()

         # print(l)

         d={}

         d['name']=l[0]

         d['price']=l[1]

         d['count']=l[2]

         res.append(d)

 print(res)