Data Handling Using | Class 12 Informatics Practices Notes

2.3.3 Accessing DataFrames Element through Indexing

DataFrames support label-based and Boolean indexing to access data elements. Label-based indexing uses the DataFrame.loc[] method, where row and column labels specify the subset of data to retrieve. Passing a single row label returns that row as a Series; passing a single column label returns the column as a Series. When row labels are integers, they are interpreted as labels, not positional indices. Multiple rows or columns can be accessed by passing lists of labels. Boolean indexing uses conditions to filter data based on values rather than labels. For example, ResultDF.loc['Maths'] > 90 returns a Boolean Series indicating which columns have values greater than 90 in the 'Maths' row. Boolean lists can also be passed to loc[] to select or omit rows. These indexing methods provide powerful ways to query and manipulate DataFrame data based on labels or conditions.

🧪 Activity: Activity 2.8: (a) Write statement to access Arnab's marks in Maths; (b) Create a DataFrame with 5 rows and get first 4 rows.

🔗 Connection: This section leads to slicing and filtering rows in DataFrames.