+= file evaluation prints a warning if zero-rows are dropped

xlap/parse.py

@@ -32,7 +32,11 @@ def _evaluate_file(file_name, stamps, kind, measured_column, sender=False):
         df.drop(_extract_stamps_by_src_and_kind(stamps, "sender"), axis=1, inplace=True)
 
     # Drop rows with value 0 (as they have probably not been written out).
-    return df[df[measured_column + "_T"] != 0]
+    res = df[df[measured_column + "_T"] != 0]
+    total, filtered = df.shape[0], res.shape[0]
+    if filtered < total:
+        print("{}: ignored {} of {} packets due to missing timestamps.".format(file_name, total-filtered, total))
+    return res
 
 
 def _diff_t_c(df, start, stop):