Init submit the testing Code

routines/CharacterCounting.m

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+ ; https://www.isharkfly.com/t/mumps-character-counting/15224
+ SET array("a")="adsakljasdira"
+ SET array("D")="DDD"
+ DO countCharsInAry(.array, .countByChar)
+ set name=""
+ f  s name=$O(countByChar(name)) q:name=""  w !,countByChar(name)
+ QUIT
+countCharsInAry(ary,countByChar)
+ SET name=""
+ FOR  SET name=$O(ary(name)) QUIT:name=""  DO  SET countByChar(name)=$$getCount(ary(name),name)
+ QUIT
+getCount(str,subStr)
+ SET count=0
+ SET position=0
+
+ FOR {
+    SET position=$FIND(str, subStr, position)
+    QUIT:position=0
+    SET count=count+1
+    SET position=position
+ }
+
+ QUIT count