If you need a literal ] you can use (regexp-quote "]") > (count-substring (regexp-quote "]") "a[rts[a3]]]]") 4
-- Jens Axel Søgaard 2014-04-15 21:09 GMT+02:00 Manfred Lotz <manfred.l...@arcor.de>: > On Rosetta code in "Count occurrences of a substring" I found this for > Racket: > > (define count-substring > (compose length regexp-match*)) > > > Example: > (count-substring "th" "the three truths") > 3 > > I like to use it for getting the number of occurences of a > list of characters in a string. > > For this I used it like this: > > (count-subsring "[a-z2;]" "arst;452") > > > Let us assume the part between the brackets could be anything. How > would I escape certain characters in order to make sure the regular > expression still works fine? > > Examples: > > -> (count-substring "[\\[]" "a[rts[a3]") > 2 > -> (count-substring "[a-z\\[]" "a[rts[a3]") > 7 > -> (count-substring "[\\]]" "a[rts[a3]") > 0 > > The first two seem to work fine, the last one doesn't. > > > > -- > Manfred > > > > > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users -- -- Jens Axel Søgaard ____________________ Racket Users list: http://lists.racket-lang.org/users
