String search: the need for a "literal" pattern
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- Subject: String search: the need for a "literal" pattern
- From: Dirk Laurie <dpl@...>
- Date: 2011年7月21日 12:05:01 +0200
In a certain string of length about 32000, a substring of length about
900, running over several lines, occurs thirty-odd times. Wishing to
count the actual number of times, I cut-and-pasted it from another
window into my Lua session:
item = [[paste here]]
Then I tried:
_,count = str:gsub(item,'')
and got `count==0`. Not expected. Thinking there may have been
invisible characters, I tried this instead:
item = str:sub(i,j)
having carefully found what i and j are. Same result.
I soon discovered that the reason is that `item` contains several
magic characters.
Quick workaround: devise a pattern that matches `item` and no other
substring of `str`. But nicer would be a pattern item that says:
"treat the rest of this pattern as literal". Say `%r`, for "raw".
Dirk