Null value for laptops database

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My Code:

os_with_null_v = laptops.loc[laptops["os_version"].isnull(),"os"]
print(os_with_null_v.value_counts())

result:
No OS 66
Linux 62
Chrome OS 27
macOS 13
Android 2
Name: os, dtype: int64

it mentioned : * The most frequent value is “No OS”. This is important to note because if there is no os, there shouldn’t be a version defined in the os_version column.

from what I understand, “No OS” reflects to “Nan” in “os version” column, why it said it has defined as a version in the “os_version” column?

Hi @ipngasi,

Technically, you’re right, “No OS” in this case is actually equivalent to NaN. Sometimes, however, datasets can contain other values for those that should be NaN, exactly like in this case, and you’ll find many other examples in your future pojects. It means that we should alsways be careful about missing values: when we check our dataset and see that it contains no NaN, it doesn’t automatically mean that it doesn’t really have missing values. Probably, they are just called in a different way.