Escaped Periods In R Regular Expressions

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My R-Fu is weak to the point of being non-existent but I think I know what’s up.

The string handling part of the R processor has to peek inside the strings to convert \n and related escape sequences into their character equivalents. R doesn’t know what \. means so it complains. You want to get the escaped dot down into the regex engine so you need to get a single \ past the string mangler. The usual way of doing that sort of thing is to escape the escape:

grepl("Processor\\.[0-9]+\\..*Processor\\.Time", names(web02))

Embedding one language (regular expressions) inside another language (R) is usually a bit messy and more so when both languages use the same escaping syntax.

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