Pandas in Action

4 The DataFrame object

This chapter covers

• Instantiating DataFrame objects from dictionaries and NumPy ndarrays
• Importing DataFrames from CSV files with the read_csv function
• Sorting DataFrame columns
• Accessing rows and columns in a DataFrame
• Setting and resetting a DataFrame index
• Renaming columns and index labels in a DataFrame

The pandas DataFrame is a two-dimensional table of data with rows and columns. As with a Series, pandas assigns an index label and an index position to each DataFrame row. Pandas also assigns a label and a position to each column. The DataFrame is two-dimensional because it requires two points of reference—a row and a column—to isolate a value from the data set. Figure 4.1 displays a visual example of a pandas