Hi Larry >From the scheme you described you will run into problems if your field name >actually contains a *. When you go to reconvert the string, it would replace >genuine *'s with $'s that aren't there.
Daniel. > On 5/08/2014, at 6:50 pm, Andy Fingerhut <andy.finger...@gmail.com> wrote: > > Or even more simply, since the thing you want to replace is a single > character, you do not need a regex to match it, but can match a string that > is not a regex at all, e.g.: > > (st/replace "**username" "*" "$") > > 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. -- 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.
