Or even more simply, since the thing you want to replace is a single character, you do not need a regex to match it, but can match a string that is not a regex at all, e.g.:
(st/replace "**username" "*" "$") The doc string for clojure.string/replace is fairly explicit on this. Andy On Mon, Aug 4, 2014 at 11:30 PM, Vincent H <vhenneb...@gmail.com> wrote: > On Tuesday, August 5, 2014 7:49:21 AM UTC+2, larry google groups wrote: >> >> I'm working on a website with a frontender who asked to be able to save >> JSON maps that contain field names such as: >> >> "$$hashKey" : "00C" >> >> The dollar signs are a violation of MongoDB limits on field names, so i >> need to convert to something else and then convert back. So I thought I >> would convert to * or !. Converting is no problem, but converting back is >> not working. I walk the deeply nested JSON objects with: >> >> (defn walk-deep-structure [next-item function-to-transform-values] >> (walk/postwalk >> (fn [%] >> (if (and (vector? %) (= (count %) 2) (keyword? (first %))) >> [(function-to-transform-values %) (second %)] >> %)) >> next-item)) >> >> which I call like: >> >> results (walk-deep-structure @future-data-return (fn [%] >> (st/replace (name (first %)) #"\*" "$")))] >> >> which doesn't work. >> >> I switch to the repl to test this: >> >> => (def f (fn [%] (st/replace (name (first %)) #"!" "$"))) >> >> => (f [:!!username "michael"]) >> >> StringIndexOutOfBoundsException String index out of range: 1 >> java.lang.String.charAt (String.java:695) >> >> or: >> >> => (def f (fn [%] (st/replace (name (first %)) #"\*" "$"))) >> >> => (f [:**username "michael"]) >> >> StringIndexOutOfBoundsException String index out of range: 1 >> java.lang.String.charAt (String.java:695) >> >> What am I doing wrong? >> > > If you use a regex as the second parameter of clojure.string/replace, then > a $ character followed by a number in the third argument is interpreted as > a reference to a captured sub-sequence in the regex ($0, $1, etc.). In your > case the $ is not followed by a number as expected, which leads to the > exception. To use a literal $ you have to escape it by preceding with a \ > (which has to be escaped itself!), or by using re-quote-replacement: > > user=> (clojure.string/replace "**username" #"\*" "\\$") > "$$username" > user=> (clojure.string/replace "**username" #"\*" > (clojure.string/re-quote-replacement "$")) > "$$username" > > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
