【Python】基础练习题-1

#练习1：从键盘输入两个数，并比较其大小，直到输入e/E退出程序
while 1:
    input_number=raw_inut("please input two numbers,enter "e" or "E" to exit:")
    try:
        if input_number.isdigit():
            lst=[]
            lst_new=lst.append(input_number)
            if lst_new[0]>lst_new[1]:
                print "%s大于%s",%(lst_new[0],lst_new[1])
            elif st_new[0]<lst_new[1]:
                print "%s小于%s",%(lst_new[0],lst_new[1])
            else:
                print "%s等于%s",%(lst_new[0],lst_new[1])
        else:
            raise TypeError
        if input_number=="e" or input_number=="E":
            break
    except TypeError:
        print "input is not a number,try again"
 
#练习2：将列表元素交替地作为建和值来创建字典
lst=[1:"a",2:"b",3:"c"]
dicts={}
for i in range(0,len(lst),2):
    dicts[lst[i]]=lst[i+1]
print dicts
 
#练习3：分别输出字符串中奇数坐标和偶数坐标的字符
num=["a","b","c","d",1,2,3,4]
oddindex_number=[]
evenindex_number=[]
for i in range(0,len(str)):
    if i%2!=0:
        oddindex_number.append(num[i])
    else:
        evenindex_number.append(num[i])
print "奇数坐标的字符为：",oddindex_number
print "偶数坐标的字符为：",evenindex_number
 
#练习4：将一个字典的 key和value 互换
dicts={1:4,2:5,3:6}
new_dicts={}
for k,v in dicts.items():
    if isinstance(v,(str,float,tuple,int,complex)):
    #print k,v
        new_dicts[v]=k
    else:
        print u"value %s不可哈希" %v
print new_dicts
 
#这是个递归的一个例子
def fib(num):
    result=[0,1]
    for i in range(num-2):
        result.append(result[-2]+result[-1])
   return result
 
ptint fib(10)