Have a look at the structure

Another method that is often used to get a rapid overview of your data is the function str(). The function str() shows you the structure of your dataset. For a data frame it tells you:

• The total number of observations (e.g. 32 car types)
• The total number of variables (e.g. 11 car features)
• A full list of the variables names (e.g. mpg, cyl … )
• The data type of each variable (e.g. num)
• The first observations

Applying the str()] function will often be the first thing that you do when receiving a new dataset or data frame. It is a great way to get more insight in your dataset before diving into the real analysis.