How to declare constants in R

Question

when I went to reproduce the example of the question "How to turn a string into Date format in R?" the command

tab<-readHTMLTable(u,header=T,skip.rows=1)

failed. The error happened because in my environment it is natural to assign the T the value of the period I am analyzing. For this reason, in my environment, T is not synonymous with TRUE and the command fails.

It made me realize that I run the serious risk of accidentally typing pi = 7, which would lead to serious errors of analysis.

The question is how to declare pi as a constant?

Answer 1

You can use the function lockBinding:

For example:

pi <- base::pi
lockBinding("pi", globalenv())

This will lock the variable pi in the constant base::pi internal in the global Environment. So if you try to define a new variable pi in the global environment with another value, the system will not leave:

pi <- 5
Error: cannot change value of locked binding for 'pi'