You may want to take a look at my library semantic-csv, which lets you cast rows as maps instead of vectors, so that you can group-by a column name instead of a positional index.
https://github.com/metasoarous/semantic-csv On Saturday, July 7, 2018 at 11:07:50 PM UTC-7, Varun J.P wrote: > > Hi All, > Thanks for the tip to use (group-by last …) > It was working fine until my csv file got updated. Now i am not sure abt > the number of columns in my csv. It could change in every row, but I still > need to group it with Heading 3 itself. > > Example of my updated CSV is as below > > Heading1 Heading 2 Heading 3 Heading 4 Heading 5 >> abc 123 Value1 newValue >> def 234 Value1 anotherValue oneMoreValue >> ghi dfgew Value1 aValue >> jkl 456 Value5 >> pqr 567 Value5 >> stu 678 value3 >> vwx sdf value4 >> yza 900 value4 > > > Now i cant use (group-by last ...) instead i tried using > > (group-by (nth (nth testvector 0) 2) testvector) where testvector is a > vector of vector but is throwing an error > >> "ClassCastException java.lang.String cannot be cast to clojure.lang.IFn >> clojure.core/group-by/fn--7011 >> (core.clj:6870)" > > > Can someone suggest a different approch > > > > > > On Tuesday, July 3, 2018 at 10:42:08 PM UTC+5:30, Philipp Neumann wrote: >> >> Hi. >> >> This is a job for (group-by last ...) >> >> Regards >> >> Varun J.P <varun...@gmail.com> schrieb am Di., 3. Juli 2018, 19:05: >> >>> My CSV file is something like the attached file which could have 'n' >>> number of line. I need to group by the values in the last column. >>> Current I believe the below code will return me a vector of vector. >>> >>> (defn read-csv-file >>> >>> [path] >>> >>> (try >>> >>> (with-open [input-file (io/reader path)] >>> >>> (let [a_list (doall (map (comp first clojure-csv.core/parse-csv) ( >>> line-seq input-file)))] >>> >>> (rest (into [] a_list)))) >>> >>> (catch Exception exception (throw exception)))) >>> >>> >>> i need to iterate through this vector of vector and create a new vector >>> of vector containing only elements of the first group, then in next >>> iteration i need the second set and so on. >>> >>> Example CSV >>> >>>> Heading1 Heading 2 Heading 3 >>>> abc 123 Value1 >>>> def 234 Value1 >>>> ghi dfgew Value1 >>>> jkl 456 Value5 >>>> pqr 567 Value5 >>>> stu 678 value3 >>>> vwx sdf value4 >>>> yza 900 value4 >>> >>> >>> >>> so when this CSV is parsed i will have something like >>> [ >>> [abc 123 Value1] >>> [def 234 Value1] >>> [ghi dfgew Value1] >>> [jkl 456 Value5] >>> [pqr 567 Value5] >>> [stu 678 value3] >>> [vwx sdf value4] >>> [yza 900 value4]] >>> So when i iterate through this i need to group the vector of vector by >>> the last column >>> so my first iteration output should be something like >>> >>> [ >>> [abc 123 Value1] >>> [def 234 Value1] >>> [ghi dfgew Value1]] >>> 2nd iteration should be >>> [ >>> [jkl 456 Value5] >>> [pqr 567 Value5]] >>> 3rd should be >>> >>> [ >>> [stu 678 value3]] >>> and so on. >>> >>> How would i achieve this in clojure. is there any build in csv parsing >>> function >>> >>> Regards >>> JP >>> >>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Clojure" group. >>> To post to this group, send email to clo...@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+u...@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+u...@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.
