I have a dataset that I am trying to analyze with PCA. The first column of my dataset is an ID and then the rest of the data. However, R adds on a first column to the dataset so that instead of the ID I want assigned to each row, it uses "1" , "2", "3", etc. as the row identifier. There is an R dataset I practiced with called mtcars - in this dataset it used the car names as each row identifier. How do I remove/prevent R from adding on a column that makes each row identifier an integer?