By default, a Pandas DataFrame is 2 dimensional with 2 axes initialized as empty Index structures. Under the basic indexing scheme, the first axis is the ‘index’ axis, which by default is a numerical index starting from 0 (using np.arange) generated for each DataFrame row. The second axis is the ‘columns’ axis, which is the set of DataFrame column labels. By default (if no column labels are specified when the DataFrame is created), the column labels are also numeric and start from 0.
