R.md

@@ -530,6 +530,23 @@ lm(y ~ x, tol=1e-14)
 
 * 参考: [https://stackoverflow.com/a/32752383](https://stackoverflow.com/a/32752383)
 
+## ビットデータ抽出
+
+```py
+  [Idx]  3  2  1  0
+# Data: FF FF FF FF (DLC = 4)
+msgdata = 0xFFFFFFFF
+
+# Layout: "2.3-2.7"
+start_bit = (2 * 8 + 3)
+#            ^       ^
+end_bit = (2 * 8 + 7) + 1
+#          ^       ^
+
+sigdata = (msgdata >> start_bit) & ((2 ** (end_bit - start_bit)) - 1)
+```
+
+
 ## References
 
 ### dplyr/tibble