Fix type errors

Author: fqqb

yamcs-client/examples/plot_with_matplotlib.py

@@ -1,5 +1,6 @@
 from datetime import datetime, timedelta, timezone
 
+import matplotlib.dates as mdates
 import matplotlib.pyplot as plt
 from yamcs.client import YamcsClient
 
@@ -13,9 +14,13 @@
     samples = archive.downsample_mean("/YSS/SIMULATOR/Altitude", start=start, stop=stop)
     x = [s.time for s in samples]
     y = [s.avg for s in samples]
+
+    mx = [mdates.date2num(t) for t in x]
+    my = [val if val is not None else float("nan") for val in y]
+
     plt.subplot(2, 1, 1)
     plt.title("Sampled at " + str(stop))
-    plt.plot(x, y)
+    plt.plot(mx, my)
     plt.xlim(start, stop)
     plt.ylabel("Altitude")
     plt.grid()
@@ -24,8 +29,12 @@
     samples = archive.downsample_mean("/YSS/SIMULATOR/SinkRate", start=start, stop=stop)
     x = [s.time for s in samples]
     y = [s.avg for s in samples]
+
+    mx = [mdates.date2num(t) for t in x]
+    my = [val if val is not None else float("nan") for val in y]
+
     plt.subplot(2, 1, 2)
-    plt.plot(x, y)
+    plt.plot(mx, my)
     plt.xlim(start, stop)
     plt.xlabel("UTC")
     plt.ylabel("Sink Rate")