python一些小的应用

#coding:utf-8

#利用dict特性去掉一个list中重复的数据
def del_repeate_data():
mylist = [1,1,2,3,4,5,4,2,5,5,5]
d = {}
for x in mylist:
d[x] = 1
mylist = list(d.keys())
print mylist
# del_repeate_data()

#生成字典
def makedir(**kwargs):
return kwargs

# dic = makedir(red=1,green=2,blue=3)
# print dic

#字符串的倒序排列
mystr = "abcdefghijk"
print mystr[::-1]

#数组的倒序排列
myarr = [1,2,3,4,45,5,6]
newarr = []
for i in reversed(myarr):
newarr.append(i)
# print newarr

#递归
'''1+2+3+...+n'''
def rec(n):
if n>0:
return n+rec(n-1)
else:# n<=0:
return 0
print rec(100)

#如果在使用递归的时候，出现条件判断，一定要把所有可能出现的条件都进行相应的处理
#求阶乘
def fac(n):
if n>0:
return n*fac(n-1)
elif n==0 or n==1:
return 1
else:
pass
print fac(-4)