Python If, Else, Elif Statements: Multiple Conditions - Screen 5 - Example unclear

I don’t understand why 1 was added to n_of_apps. Though I know the condition is greater than or equal to 4 but how does this connect with 1 being added…??

Here we have to find out how many apps have a rating of 4.0 or more.
First, we initialized a variable n_of_apps with a value of 0.
In the for loop we are checking whether the rating is 4.0 or more, if it’s more then we are incrementing the value of n_of_apps by 1. To increment, we add 1 to the previous value of n_of_apps, whenever the if condition evaluates to True.

Hope it’s clear.

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Why do we increment the value by 1 when the rating is more than 4? I mean what’s the logic behind it??

We are using n_of_apps to keep track of the count of apps having a rating of 4 or greater than 4 (because here we want to count only the apps with a high rating, starting from 4). Initially we have set it to 0. Whenever we find an app with a rating of 4 or more, we will increase the value of n_of_apps by 1.

Let’s consider the first 5 rows and check the data

apps_data = apps_data[:5]
['id', 'track_name', 'size_bytes', 'currency', 'price', 'rating_count_tot', 'rating_count_ver', 'user_rating', 'user_rating_ver', 'ver', 'cont_rating', 'prime_genre', 'sup_devices.num', 'ipadSc_urls.num', 'lang.num', 'vpp_lic'], 
['284882215', 'Facebook', '389879808', 'USD', '0.0', '2974676', '212', '3.5', '3.5', '95.0', '4+', 'Social Networking', '37', '1', '29', '1'], 
['389801252', 'Instagram', '113954816', 'USD', '0.0', '2161558', '1289', '4.5', '4.0', '10.23', '12+', 'Photo & Video', '37', '0', '29', '1'], 
['529479190', 'Clash of Clans', '116476928', 'USD', '0.0', '2130805', '579', '4.5', '4.5', '9.24.12', '9+', 'Games', '38', '5', '18', '1'], 
['420009108', 'Temple Run', '65921024', 'USD', '0.0', '1724546', '3842', '4.5', '4.0', '1.6.2', '9+', 'Games', '40', '5', '1', '1']

With the following code you could see that, when we come across a rating of 4.0 or more and we increase the value of n_of_apps by 1.

n_of_apps = 0
for row in apps_data[1:]:
    rating = float(row[7])
    if rating >= 4.0:
        n_of_apps = n_of_apps + 1
    print('Rating is:', rating, 'and n_of_apps is:',n_of_apps)
Rating is: 3.5 and n_of_apps is: 0
Rating is: 4.5 and n_of_apps is: 1
Rating is: 4.5 and n_of_apps is: 2
Rating is: 4.5 and n_of_apps is: 3

Let know if you have any doubts.

Hi @mursuljamil ,

It seems like the exercise asks you to count the number of times the rating in row[7] is 4.0 or greater The count is stored in variable n_of_apps

n_of_apps = 0
‘’’ n_of_apps variable starts at 0 and increases to 1 after each loop, if the rating is > =4

for row in apps_data[1]:
rating = float(row[7]) # let’s pretend the rating is 4.5
if rating >= 4.0: # triggers if statement
n_of_apps = n_of_apps + 1 # adds 1 to n_of_apps variable outside for loop

If you did not add the +1 you would overwrite the balance to 0 versus adding +1 to increase the n_of_apps variable by 1. For example, let’s pretend the rating is 4.6 in the 2nd for loop iteration. The “if statement” is triggered and +1 is added to n_of_apps variable. The n_of_apps variable is now 2. If you did not add n_of_apps +1 the n_of_apps variable outside the loop would reset to 0 again instead of adding 1. Each loop adds +1 to the n_of_apps outside the for loop.
You can also write as n_of_apps += 1 which means the same thing as n_of_apps = n_of_apps + 1