diff --git a/stat/frequency.py b/stat/frequency.py
new file mode 100644
index 0000000..48f5cb3
--- /dev/null
+++ b/stat/frequency.py
@@ -0,0 +1,76 @@
+import argparse
+import json
+from pathlib import Path
+import fastparquet
+import pandas as pd
+import plotly.express as px
+import plotly.graph_objects as go
+
+
+def _extract_identifier(row: pd.Series) -> str:
+ """Extracts PGN from metadata or falls back to CAN ID."""
+ meta = row.get('j1939_metadata')
+ if pd.isna(meta):
+ return f"{row['ID']} "
+ if isinstance(meta, str):
+ try:
+ meta = json.loads(meta)
+ except json.JSONDecodeError:
+ return f"{row['ID']}"
+ if isinstance(meta, dict) and 'PGN' in meta:
+ return f"PGN: {meta['PGN']} "
+ return f"{row['ID']}"
+
+
+def load_data(file_path: Path) -> pd.DataFrame:
+ """Loads Parquet file and adds an Identifier column."""
+ df = pd.read_parquet(file_path)
+ df['Identifier'] = df.apply(_extract_identifier, axis=1)
+ return df
+
+
+def calculate_frequency(df: pd.DataFrame) -> pd.DataFrame:
+ """Calculates frequency counts and percentages for identifiers."""
+ freq_df = df['Identifier'].value_counts().reset_index()
+ freq_df.columns = ['Identifier', 'Count']
+ total_messages = freq_df['Count'].sum()
+ freq_df['Percentage'] = (freq_df['Count'] / total_messages * 100).round(2)
+ return freq_df.sort_values('Count', ascending=True)
+
+
+def visualize_frequency(stats_df: pd.DataFrame, title: str = "CAN Bus Message Frequency") -> go.Figure:
+ """Generates an interactive Plotly horizontal bar chart with a logarithmic x-axis."""
+ fig = px.bar(
+ stats_df, y='Identifier', x='Count', orientation='h', title=title, log_x=True,
+ labels={'Identifier': 'PGN / CAN ID', 'Count': 'Message Count'},
+ color='Count', color_continuous_scale='Turbo',
+ hover_data={'Percentage': ':.2f', 'Count': True, 'Identifier': True}
+ )
+
+ fig.update_layout(
+ height=max(600, len(stats_df) * 18), width=1000,
+ xaxis_title='Total Message Count (Log Scale)', yaxis_title='PGN or CAN ID',
+ yaxis={'categoryorder': 'total ascending'},
+ plot_bgcolor='rgba(0,0,0,0)', paper_bgcolor='white',
+ font=dict(family="Segoe UI, Arial, sans-serif", size=12),
+ hoverlabel=dict(bgcolor="white", font_size=13, font_family="Segoe UI"),
+ margin=dict(l=250, r=50, t=80, b=50),
+ title=dict(font=dict(size=20), x=0.5)
+ )
+
+ fig.update_traces(
+ hovertemplate="%{y}
Count: %{x:,}
Share: %{customdata[0]}%"
+ )
+ return fig
+
+if __name__ == "__main__":
+ parser = argparse.ArgumentParser(description="Analyze CAN bus Parquet data.")
+ parser.add_argument("-i", "--input", type=Path, required=True)
+ parser.add_argument("-o", "--output", type=Path, default=Path("can_analysis_report.html"))
+ parser.add_argument("-t", "--title", type=str, default="CAN Bus Message Frequency by PGN / ID")
+ args = parser.parse_args()
+
+ df = load_data(args.input)
+ stats_df = calculate_frequency(df)
+ fig = visualize_frequency(stats_df, title=args.title)
+ fig.write_html(str(args.output), include_plotlyjs='cdn')