I have a data set with prices of 6 major stocks i.e., Google, Amazon etc.

My plan is to create a plot which would show a percent change, pct_change()of column known as close_value.

As you can see my ticker_symbol is an object. I tried and changed it to float because of the string error but then I lost all ticker names i.e. I executed returns.close_value.plot();.

How not to lose stock names while plotting?