attach function

https://awakeningdatascientist.wordpress.com/2015/07/16/r-of-the-day-attach/

The attach function in R is a powerful tool in base R that allows you to, well, attach a specific database to a search path. In other words, attach allows you to reference database variables without using the “$” extractor. For example, without using the attach function (using the Iris data set from R):