Lets say I have a string "Hello." I want to see if this string contains a period:
text <- "Hello."
results <- grepl(".", text)
This returns results as TRUE, but it would return that as well if text is "Hello" without the period.
I'm confused, I can't find anything about this in the documentation and it only does this for the period.
Any ideas?
See the differences with these examples
> grepl("\\.", "Hello.")
[1] TRUE
> grepl("\\.", "Hello")
[1] FALSE
the . means anything as pointed out by SimonO101, if you want to look for an explicit . then you have to skip it by using \\. which means look for a .
R documentation is extensive on regular expressions, you can also take a look at this link to understand the use of the dot.
I use Jilber's approach usually but here are two other ways:
> grepl("[.]", "Hello.")
[1] TRUE
> grepl("[.]", "Hello")
[1] FALSE
> grepl(".", "Hello.", fixed = TRUE)
[1] TRUE
> grepl(".", "Hello", fixed = TRUE)
[1] FALSE