Answer:
See explanation below and try out this code to see what exactly is happening
# Program
j = 3
z = { ] # empty dictionary
print(z)
z[2] = 1 # z
print(z)
z[7] = 3
print(z)
z[5] = 2
print(z) # prints out {2: 1, 7: 3, 5: 2}
for l in z:
print("Initial value of j = ", j)
print("Value of l(key) = ", l)
j += l
print("Updated value of j = ", j)
print("Final value of j=", j)
Step-by-step explanation:
What you have is a dictionary object. We use { } to represent a dictionary. A dictionary consists of keys and values related to the keys. For example, you can have a dictionary which contains names of students and their GPAs
This is declared as
student_grades = {"Amy": 4.3, "Zach":4.0", "Bill": 3.2}
The names are referred to as keys and the GPA as values
You can also have both key and value as integers. Fir example you could store the cubes of numbers from 1 to 5 in a dictionary
cubes = {1: 1, 2:8, 3: 27, 4: 64, 5:125}
If you wanted to add the cube for 6 then you would use cubes[6] = 216 This creates a new entry in the dictionary 6:216 so that the dictionary is now
cubes = {1: 1, 2:8, 3: 27, 4: 64, 5:125, 6:216}
In this short program here is what is happening
j = 3 # variable j created and value set to 3
z = { } # this creates an empty dictionary named z
z[2] = 1 #adds an entry with key = 2 and value = 1; z = {2 : 1}
z[7} = 3 #key 7 and value 2 added => z = {2 : 1, 7 : 3}
z[5] = 2 #key 5, value 2 => z = {2: 1, 7 : 3, 5 : 2}
So now there are 3 entries in the dictionary i.e. 3 pairs of key-values
When you iterate through the dictionary as in
for l in z:
- you are actually iterating over the keys so l = 2, 7 and 5 on each iteration
So you are accumulating the key values
Here is what happens
First execution of loop => j = 3 , l = 2 (first key =2), j = 3 + 2 = 5
Second time: l = 7 (second key value) , j = 5 + 7 = 12
Third time: l = 5, j = 12 + 5 = 17
There is a lot more to dictionaries and sometimes it can get complicated. Suggest you search the internet for the same
Putting print() statements also helps you visualize what is happening. Code is provided in the answer section to help you