Predict the output of the following code:
S="RAIN"
L=[4,8,12,16]
D={}
for I in range(len(S)):
if I%2==0:
D[L.pop()]=S[I]
else:
D[L.pop(0)]=I+6
for K,V in sorted(D.items()):
print(K,V,sep="*")
Answer:
Answer by student
The output of the following code is:
4*7
8*9
12*I
16*R
Detailed answer by teachoo
- The code given below defines a string S, a list L, and an empty dictionary D.
- Then it loops through the indices of S using a for loop.
- For each index I, it checks if it is even or odd using the modulo operator (%).
- If it is even, it pops the last element of L using the pop() method and assigns it as a key to the dictionary D, with the corresponding character of S as the value.
- If it is odd, it pops the first element of L using the pop(0) method and assigns it as a key to the dictionary D, with the index I plus 6 as the value.
- After the loop, it prints the key-value pairs of D in sorted order using the sorted() function and a for loop, with an asterisk (*) as the separator.
-
To predict the output of this code, we need to trace the values of S, L, D, and I in each iteration of the loop. We can use a table to do this:
Iteration
I
S[I]
L
D
0
0
R
[4, 8, 12]
{16: ‘R’}
1
1
A
[8, 12]
{16: ‘R’, 4: 7}
2
2
I
[8]
{16: ‘R’, 4: 7, 12: ‘I’}
3
3
N
[]
{16: ‘R’, 4: 7, 12: ‘I’, 8: 9}
- After the loop, D contains four key-value pairs: {16: ‘R’, 4: 7, 12: ‘I’, 8: 9} . The sorted() function returns a list of tuples containing the key-value pairs of D in sorted order by default. Therefore, the list returned by sorted(D.items()) is [(4, 7), (8, 9), (12, ‘I’), (16, ‘R’)]. Then we loop through this list using a for loop and print each tuple with an asterisk (*) as the separator using the sep parameter of the print() function. Therefore, the output of the code is:
4*7
8*9
12*I
16*R
