R 101

Sometimes when you open a data file (lets say a .csv), variables will be recognized as factor whereas it should be numeric. It is therefore tempting to simply convert the variable to numeric using as.numeric(). Big mistake! If you use directly as.numeric() on a variable of the type factor, R will returns the levels of the factor rather the actual values. To overcome this hassle, you should first convert the variable into a string with as. [Read More]