Irritating quirks of the R statistical software

If I write these down, then hopefully I will be faster by avoiding these errors in the future.

• reshape in Dplyr does not support categorical (as opposed to numercial) columns, because it expects time series.  Use pivot_longer from tidyverse instead 
• '.' is a special character in gsub, it needs escaping as '\\.'
• There is a bug in R which leads to crashes if the time is 00:00:00, so use 00:00:01 instead
• Columns cannot start with a numerical digit.  '3pm_to_5pm' must be written as 'Three_pm_to_five_pm'.