Add solution for Challenge 6 by mick4711

Author: mick4711

challenge-6/solution-template.go

@@ -2,11 +2,9 @@
 package challenge6
 
 import (
-	"bytes"
+	// Add any necessary imports here
 )
 
-// Add any necessary imports here
-
 // CountWordFrequency takes a string containing multiple words and returns
 // a map where each key is a word and the value is the number of times that
 // word appears in the string. The comparison is case-insensitive.
@@ -20,10 +18,5 @@ import (
 // Output: map[string]int{"the": 2, "quick": 1, "brown": 1, "fox": 1, "jumps": 1, "over": 1, "lazy": 1, "dog": 1}
 func CountWordFrequency(text string) map[string]int {
 	// Your implementation here
-	words := bytes.Fields([]byte(text))
-	counts := make(map[string]int, len(words))
-	for _, word := range words {
-		counts[string(bytes.ToLower(word))]++
-	}
-	return counts
-}
+	return nil
+} 

challenge-6/submissions/mick4711/solution-template.go

@@ -0,0 +1,43 @@
+// Package challenge6 contains the solution for Challenge 6.
+package challenge6
+
+import (
+	"bytes"
+	"strings"
+	"unicode"
+)
+
+// CountWordFrequency takes a string containing multiple words and returns
+// a map where each key is a word and the value is the number of times that
+// word appears in the string. The comparison is case-insensitive.
+//
+// Words are defined as sequences of letters and digits.
+// All words are converted to lowercase before counting.
+// All punctuation, spaces, and other non-alphanumeric characters are ignored.
+//
+// For example:
+// Input: "The quick brown fox jumps over the lazy dog."
+// Output: map[string]int{"the": 2, "quick": 1, "brown": 1, "fox": 1, "jumps": 1, "over": 1, "lazy": 1, "dog": 1}
+func CountWordFrequency(text string) map[string]int {	// Your implementation here
+	// use whitespace and dash to parse out words
+	f := func(c rune) bool {
+		return unicode.IsSpace(c) || c == '-'
+	}
+	words := bytes.FieldsFunc([]byte(text), f)
+	
+	// initialise return map
+	counts := make(map[string]int, len(words))
+	
+	// iterate through words filtering out invalid chars
+	for _, word := range words {
+		var b strings.Builder
+		word = bytes.ToLower(word)
+		for _, char := range word {
+			if (char > 96 && char < 123) || (char > 47 && char < 58) {
+				b.WriteByte(char)
+			}
+		}
+		counts[b.String()]++
+	}
+	return counts
+}