Types of Data on R

There are different types of data on R. I use type here as a technical term, rather than merely a synonym of “variety”.  There are three main types of data:

1. Numeric: ordinary numbers
2. Character: not treated as a number, but as a word. You cannot add two characters, even if they appear to be numerical. Characters have “inverted commas” around them.
3. Date: can be used in time series analysis, like a time series plot.

To diagnose the type of data you’re dealing with, use class()

You can convert data between types. To convert to:

1. Numeric: as.numerical()
2. Character: as.character()
3. Date: as.Date()

Note that to convert a character or numeric to a date, you may need to specify the format of the date:

• ddmmyyyy: as.Date(x, format=”%d%m%Y”) *default, so format needn’t be specified
• mmddyyyy: as.Date(x, format=”%m%d%Y”)
• dd-mm-yyyy: as.Date(x, format=”%d-%m-%Y”)
• dd/mm/yyyy: as.Date(x, format=”%d/%m/%Y”)
• if the month is named, like 12February1989: as.Date(x, format=”%d%B%Y”)
• if the month is short-form named, like 12Feb1989: as.Date(x, format=”%d%b%Y”)
• if the year is in two digit form, like 12Feb89: as.Date(x, format=”%d%m%y”)
• if the date in mmyyyy form: as.yearmon(x, format=”%m%Y”) *from zoo package
• if date includes time, like 21/05/2012 21:20:30: as.Date(x, format=”%d/%m/%Y %H:%M:%S)

Abbas Keshvani