TASK
You are given a set and number of other sets. These number of sets have to perform some specific mutation operations on set .
Your task is to execute those operations and print the sum of elements from set .
Input Format
The first line contains the number of elements in set .
The second line contains the space separated list of elements in set .
The third line contains integer , the number of other sets.
The next lines are divided into parts containing two lines each.
The first line of each part contains the space separated entries of the operation name and the length of the other set.
The second line of each part contains space separated list of elements in the other set.
len(set(A))
len(otherSets)
Output Format
Output the sum of elements in set .
16
1 2 3 4 5 6 7 8 9 10 11 12 13 14 24 52
4
intersection_update 10
2 3 5 6 8 9 1 4 7 11
update 2
55 66
symmetric_difference_update 5
22 7 35 62 58
difference_update 7
11 22 35 55 58 62 66
SOLUTION:
# Enter your code here. Read input from STDIN. Print output to STDOUT
num_elements = int(input())
A = set(input().split())
N = int(input())
for i in range(N):
(cmd,num) = input().split()
otherset = set(input().split())
eval('A.{}({})'.format(cmd,otherset))
#eval('A.' + cmd + '(otherset)')
print(sum(map(int,A)))
题目来自hackerank
为什么eval函数里的operation需要和其他两个部位隔开呢，eval不是一个解析字符串的函数嘛，如果按#后面写的话算不算是两个字符串加一个变量了。。被引号括起来的部分也是变量呀。。如果有大神看到了麻烦解答以下。
答案:38
