Right now, the data is somewhere between long and wide format. Use melt() to make it completely long format. Hint: date and ticker are our ID variables (they uniquely identify each row). We need to...

Right now, the data is somewhere between long and wide format. Use melt()

to make it completely long format. Hint: date and ticker are our ID variables

(they uniquely identify each row). We need to melt the rest so that we don't have

separate columns for open, high, low, close, and volume.