learning about regexp capture groups, seems like it could be quite useful...

learning/regexp-capture-groups.go

@@ -0,0 +1,32 @@
+package learning
+
+import (
+	"regexp"
+	"strings"
+
+	"github.com/alexchao26/advent-of-code-go/cast"
+)
+
+func CaptureBingoBoard(board string) [][]int {
+	var nums [][]int
+	// parens create indexed capture groups
+	// when used with (*regexp).FindStringSubmatch a string slice is returned
+	pattern := regexp.MustCompile(`\s?(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)`)
+
+	for _, row := range strings.Split(board, "\n") {
+		matches := pattern.FindStringSubmatch(row)
+		if matches == nil {
+			panic("row does not match pattern: " + row)
+		}
+
+		// submatch[0] is the entire string
+		// submatch[1:] are the captured groups that i'm interested in
+		var rowNums []int
+		for _, v := range matches[1:] {
+			rowNums = append(rowNums, cast.ToInt(v))
+		}
+		nums = append(nums, rowNums)
+	}
+
+	return nums
+}