Adding new columns with [] and .insert()
New columns can be added to a data frame using the [] operator. Let's add a new column named RoundedPrice which will represent the rounding of values in the Price column.
The way that pandas performs this is by first selecting the Price column's data from sp500 and then all of the values in that Series are rounded. Then pandas aligns this new Series with the copy DataFrame and adds it as a new column named RoundedPrice. The new column is added to the end of the columns index.
The .insert() method can be used to add a new column at a specific location. The following inserts the RoundedPrice column between Sector and Price:
