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python練習(一)

val lte imp sts else 練習 filter [0 pen

1. 實現1-100的所有的和

def qiuhe(x, y):
return x + y


he = 0
for i in xrange(1, 101):
he =qiuhe(he,i)
print (he)

2. 實現1-500所有奇數的和

def is_odd(x):
return x % 2 == 1
def qiuhe(x, y):
return x + y

he = 0
for i in filter(is_odd,xrange(1,501)):
print (i)
he = qiuhe(he, i)
print (he)

3.求1+ 2! + 3! + 4! + ……20!的和

def qiuhe(x, y):
return x + y

def jiecheng(n):
if(n<=1):
return 1
else:
return jiecheng(n-1)*n

he = 0
for i in xrange(1, 21):
he +=jiecheng(i)
print (he)

4.對指定一個list進行排序[2,32,43,453,54,6,576,5,7,6,8,78,7,89]

list.sort() 在本地進行排序,不返回副本
或者
def cmp_value(x,y):
if x > y :
return 1
elif x < y:
return -1
else:
return 0

listsorted=[2,32,43,453,54,6,576,5,7,6,8,78,7,89]
so=sorted(listsorted,cmp=cmp_value)
print (so)

5.字典排序,字符串, list, tuple常用方法

字典排序:

import operator
d = {‘data1‘:3, ‘data2‘:1, ‘data3‘:2, ‘data4‘:4}
print (sorted(d.iteritems(),key=operator.itemgetter(1)))

list:
classmates = [‘Michael‘, ‘Bob‘, ‘Tracy‘]
#len
print (len(classmates))

#index
print (classmates[0])

#-1
print (classmates[-1])

#append
classmates.append(‘Adam‘)
print (classmates)

#insert
classmates.insert(1,‘Jack‘)
print (classmates)

#pop
classmates.pop(1)
print (classmates)





python練習(一)