In wadpac/GGIR: Raw Accelerometer Data Analysis

Various GGIR parameters expect us to provide a date or time format. R uses codes to define elements of a date or time format.

The table below shows the individual codes and their meaning:

Code | Value ----------|---------------------- "%d" | Day of the month (decimal number) "%m" | Month (decimal number) "%b" | Month (abbreviated) "%B" | Month (full name) "%y" | Year (2 digit) "%Y" | Year (4 digit) "%h" | Hour "%H" | Decimal hours (24 hour) "%I" | Decimal hours (12 hour).0 "%M" | Decimal minute "%S" | Decimal second "%a" | Abbreviated weekday "%A" | Full weekday "%p" | Locale-specific AM/PM "%z" | Offset from GMT "%Z" | Time zone (character)

The table below shows examples of how to define time or data format using the above codes.

Example time or date format | R code to describe this format ----------------------------|---------------------- "12-Mar-2025 15:05:02" | "%d-%b-%Y %H:%M:%S" "12-Mar-25 15:05:02" | "%d-%b-%y %H:%M:%S" "12-03-25 15:05:02" | "%d-%m-%y %H:%M:%S" "2025/03/20 15:05:02" | "%Y/%m/%d %H:%M:%S" "20/03/2025 15:05:02" | "%d/%m/%Y %H:%M:%S" "20/03/2025 03:05:02 PM" | "%d/%m/%Y %I:%M:%S %p" "Thu Mar 2025 03:11:06 PM"| "%a %b %Y %I:%M:%S %p" "12-Mar-2025" | "%d-%b-%Y" "2025/03/20" | "%Y/%m/%d"

For example we may set:

• rmc.format.time = "%d/%m/%Y %H:%M:%S" when we see "20/03/2025 15:05:02" in a csv file with raw data.

• extEpochData_timeformat = "%d-%m-%Y %H:%M:%S" when we see "12-03-2025 15:05:02" in an externally derived epoch data file such as the Philips health band .xlsx data files.

wadpac/GGIR documentation built on June 15, 2025, 12:48 p.m.