python练习4
python期末练习：列表
目录
1. 列表的简单运算
2. 两两相乘再相加
3. 考试成绩优秀
4. 高于平均分
5. 求双阶乘
6. 低洼地编辑
1. 列表的简单运算
ls=eval(input())count_odd=0
count_even=0
sum_odd=0
sum_even=0for i in ls:if i%2==1:count_odd+=1sum_odd+=ielse:count_even+=1sum_even+=iavg=sum(ls)/len(ls)print(count_odd,count_even,sum_odd,sum_even,avg)
2. 两两相乘再相加
ls=eval(input())result = 0
for i in range(len(ls)):for j in range(i+1, len(ls)):result += ls[i] * ls[j]print(result)3. 考试成绩优秀
ls=eval(input())count=0
for i in ls:if i>85:count+=1avg=sum(ls)/len(ls)print(count,avg)4. 高于平均分
ls=[['唐三藏',98],['孙悟空',88],['猪八戒',46],['沙和尚',62],['白龙马',100]]ls1=[]
sum1=0
for i in ls:sum1+=i[1]avg=sum1/len(ls)
for i in ls:if i[1]>avg:ls1.append(i[0])print(ls1)
print(len(ls1))5. 求双阶乘
ls1=eval(input())ls2=[]for i in ls1:b=1for i in range(i,0,-2):
#从i开始，每次递减2，到0之前结束，保证了相同的奇偶，以及不会乘到0b*=ils2.append(b)print(ls2)6. 低洼地
ls=eval(input())count=0
for i in range(1,len(ls)-1):if (ls[i]<ls[i-1] and ls[i]<ls[i+1]) or (ls[i]==ls[i-1] and ls[i]<ls[i+1]):
#注意出现平地时的情况，通过逻辑运算符描述，and的优先级高于or，此处括号可去，不影响运算count+=1print(count)