Run error: Profitable App Profiles for the App Store and Google Play Markets

Screen Link: https://app.dataquest.io/m/350/guided-project%3A-profitable-app-profiles-for-the-app-store-and-google-play-markets/4/removing-duplicate-entries-part-one

Your Code: Enclose your code in 3 backticks like this to format properly: ```def explore_data(dataset, start, end, rows_and_columns=False):
dataset_slice = dataset[start:end]
for row in dataset_slice:
print(row)
print(’\n’) # adds a new (empty) line between rows

if rows_and_columns:
    print('Number of rows:', len(dataset))
    print('Number of columns:', len(dataset[0]))

print(android_header)
print(’\n’)
explore_data(android, 0, 3, True)


What I expected to happen:  i have run the code once and it ran, but after saving it and i shut down the system to do some other things whenever i come back to him to continue the project, it keeps giving me error  and as a result i cannot really progress. i have been battling with it for some days now.

What actually happened: ```NameErrorTraceback (most recent call last)
<ipython-input-4-50b364022b3a> in <module>()
      9         print('Number of columns:', len(dataset[0]))
     10 
---> 11 print(android_header)
     12 print('\n')
     13 explore_data(android, 0, 3, True)

NameError: name 'android_header' is not defined
``` to format properly

Other details:  the file is opened already but  ```open('AppleStore.csv', encoding='utf8')

open('googleplaystore.csv', encoding='utf8')

output  ```<_io.TextIOWrapper name='googleplaystore.csv' mode='r' encoding='utf8'> ```

I’m afraid that there isn’t much context here to go off of — any chance you can attach your .ipynb file to this thread so we can take a closer look?