Parse pattern matching

Continuing my struggle with parsing, I have a folder of files, and I want to do something with some of them but not all of them. The names are like the ones in the sample below. What I want to do is, process those files whose names BEGIN with "CV_Permits" and SKIP all the other files. Since I don't know how to specify that the names must BEGIN WITH "CV_Permits" it would sort of work to SKIP those files that DO start with "Log" however that is not ideal because the folder does contain other files that start with neither "CV_Permits" nor "Log." If anyone can offer guidance, I will put the solution into my collection of parsing examples so I never will have to ask again. Thank you. I can brute-force a non-parsing solution, but it seems like parsing would be smoother. R E B O L [] FILENAMES: [ %CV_Permits_2-1-2018.txt %CV_Permits_2-4-2018.txt %Log_CV_Permits_2-1-2018.txt %Log_CV_Permits_2-4-2018.txt ] foreach ID FILENAMES [ ;; -- Would prefer the reverse logic of deciding which ones to ;; -- KEEP rather than which ones to SKIP. either parse to-string ID ["Log_"] [ print ["Skip " ID] ] [ print ["Process " ID] ] ] halt

You're looking for some fairly elementary pattern matching here that PARSE can certainly handle, though FIND will also be your friend here: PARSE: remember that for parse to return TRUE, you have to provide a rule that describes the input string: foreach ID FILENAMES [ if parse ID ["CV_Permits_" to end][ ; to end will match everything after your prefix print ["Process:" ID] ] ] FIND: the /MATCH refinement will only return 'truthy' if the search string is at the current index: foreach ID FILENAMES [ if find/match ID "CV_Permits_" [ print ["Process:" ID] ] ]

;; Here is how I do it. ;; First, I write out what needs to be done in p-code. ;; And then I try code at the console ;; For every file, i.e., for all ;; REBOL should try to match those beginning with CV ;; -while ignore the rest of the filename crud ;; REBOL should add those that have matched to a block names: copy [] forall filenames [ -parse filenames/1 [ "CV" skip to end ( ---append names filenames/1 --) -] ] ;; non-parse way names: copy [] forall filenames [ -if equal? 1 index? find filenames/1 %CV [append names filenames/1] ] Why? Hint: We're asking REBOL to append to a block! only those finds that have a "head view," i.e., have an index position of one See? views: copy [] forall filenames [ -if i: index? find filenames/1 %CV [ --append views join "view of find starts at: " i -] ] new-line/all views on probe views