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

learning/learning.go

@@ -0,0 +1,3 @@
+// Package learning is for testing random things that might be useful but I need
+// to spend some time playing around with
+package learning

learning/regexp-capture-groups.go

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+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
+}

learning/regexp-capture-groups_test.go

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+package learning
+
+import (
+	"reflect"
+	"testing"
+)
+
+var (
+	example1 = `22 13 17 11  0
+ 8  2 23  4 24
+21  9 14 16  7
+ 6 10  3 18  5
+ 1 12 20 15 19`
+
+	example2 = ` 3 15  0  2 22
+ 9 18 13 17  5
+19  8  7 25 23
+20 11 10 24  4
+14 21 16 12  6`
+
+	example3 = `14 21 17 24  4
+10 16 15  9 19
+18  8 23 26 20
+22 11 13  6  5
+ 2  0 12  3  7`
+)
+
+func TestCaptureBingoBoard(t *testing.T) {
+	type args struct {
+		board string
+	}
+	tests := []struct {
+		name string
+		args args
+		want [][]int
+	}{
+		{
+			name: "example 1",
+			args: args{
+				board: example1,
+			},
+			want: [][]int{
+				{22, 13, 17, 11, 0},
+				{8, 2, 23, 4, 24},
+				{21, 9, 14, 16, 7},
+				{6, 10, 3, 18, 5},
+				{1, 12, 20, 15, 19},
+			},
+		},
+		{
+			name: "example 2",
+			args: args{
+				board: example2,
+			},
+			want: [][]int{
+				{3, 15, 0, 2, 22},
+				{9, 18, 13, 17, 5},
+				{19, 8, 7, 25, 23},
+				{20, 11, 10, 24, 4},
+				{14, 21, 16, 12, 6},
+			},
+		},
+		{
+			name: "example 3",
+			args: args{
+				board: example3,
+			},
+			want: [][]int{
+				{14, 21, 17, 24, 4},
+				{10, 16, 15, 9, 19},
+				{18, 8, 23, 26, 20},
+				{22, 11, 13, 6, 5},
+				{2, 0, 12, 3, 7},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := CaptureBingoBoard(tt.args.board); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("CaptureBingoBoard() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}