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| 1 | +""" pyplots.ai |
| 2 | +parliament-basic: Parliament Seat Chart |
| 3 | +Library: plotly 6.5.0 | Python 3.13.11 |
| 4 | +Quality: 93/100 | Created: 2025-12-30 |
| 5 | +""" |
| 6 | + |
| 7 | +import numpy as np |
| 8 | +import plotly.graph_objects as go |
| 9 | + |
| 10 | + |
| 11 | +# Data - Fictional parliament with neutral party names (avoiding political references) |
| 12 | +parties = [ |
| 13 | + {"name": "Progressive Alliance", "seats": 145, "color": "#306998"}, |
| 14 | + {"name": "Civic Union", "seats": 118, "color": "#FFD43B"}, |
| 15 | + {"name": "Green Future", "seats": 52, "color": "#2CA02C"}, |
| 16 | + {"name": "Liberty Party", "seats": 48, "color": "#9467BD"}, |
| 17 | + {"name": "Reform Coalition", "seats": 35, "color": "#FF7F0E"}, |
| 18 | + {"name": "Independent Group", "seats": 22, "color": "#E377C2"}, |
| 19 | +] |
| 20 | + |
| 21 | +total_seats = sum(p["seats"] for p in parties) |
| 22 | +majority_threshold = total_seats // 2 + 1 |
| 23 | + |
| 24 | +# Calculate seat positions in semicircular arrangement |
| 25 | +# Seats are arranged by angle across all rows, with parties grouped from left to right |
| 26 | +n_rows = 7 if total_seats <= 500 else 9 |
| 27 | +inner_radius = 0.4 |
| 28 | +row_spacing = 0.11 |
| 29 | + |
| 30 | +# Calculate seats per row (outer rows have more seats due to larger circumference) |
| 31 | +row_seats = [] |
| 32 | +for row in range(n_rows): |
| 33 | + radius = inner_radius + row * row_spacing |
| 34 | + # Seats proportional to arc length (radius) |
| 35 | + seats_in_row = int(total_seats * radius / sum(inner_radius + i * row_spacing for i in range(n_rows))) |
| 36 | + row_seats.append(max(seats_in_row, 1)) |
| 37 | + |
| 38 | +# Adjust to match total seats exactly |
| 39 | +diff = total_seats - sum(row_seats) |
| 40 | +for i in range(abs(diff)): |
| 41 | + idx = (n_rows - 1 - i % n_rows) if diff > 0 else (i % n_rows) |
| 42 | + row_seats[idx] += 1 if diff > 0 else -1 |
| 43 | + |
| 44 | +# Generate all seat positions sorted by angle (left to right = pi to 0) |
| 45 | +all_seats = [] |
| 46 | +for row, n_seats in enumerate(row_seats): |
| 47 | + radius = inner_radius + row * row_spacing |
| 48 | + for i in range(n_seats): |
| 49 | + # Angle from left (pi) to right (0) - seats go left to right |
| 50 | + angle = np.pi - (i + 0.5) * np.pi / n_seats |
| 51 | + all_seats.append({"x": radius * np.cos(angle), "y": radius * np.sin(angle), "angle": angle, "row": row}) |
| 52 | + |
| 53 | +# Sort all seats by angle (descending = left to right in parliament view) |
| 54 | +all_seats.sort(key=lambda s: -s["angle"]) |
| 55 | + |
| 56 | +# Assign parties to seats (parties fill seats from left to right) |
| 57 | +positions = [] |
| 58 | +seat_idx = 0 |
| 59 | +for party in parties: |
| 60 | + for _ in range(party["seats"]): |
| 61 | + if seat_idx < len(all_seats): |
| 62 | + seat = all_seats[seat_idx] |
| 63 | + positions.append( |
| 64 | + {"x": seat["x"], "y": seat["y"], "party": party["name"], "color": party["color"], "row": seat["row"]} |
| 65 | + ) |
| 66 | + seat_idx += 1 |
| 67 | + |
| 68 | +# Create figure |
| 69 | +fig = go.Figure() |
| 70 | + |
| 71 | +# Add seats grouped by party for legend |
| 72 | +for party in parties: |
| 73 | + party_positions = [p for p in positions if p["party"] == party["name"]] |
| 74 | + fig.add_trace( |
| 75 | + go.Scatter( |
| 76 | + x=[p["x"] for p in party_positions], |
| 77 | + y=[p["y"] for p in party_positions], |
| 78 | + mode="markers", |
| 79 | + marker=dict(size=14, color=party["color"], line=dict(color="white", width=1)), |
| 80 | + name=f"{party['name']} ({party['seats']})", |
| 81 | + hovertemplate=f"{party['name']}<br>Seats: {party['seats']}<extra></extra>", |
| 82 | + ) |
| 83 | + ) |
| 84 | + |
| 85 | +# Add majority threshold arc (dashed line) |
| 86 | +threshold_angle = np.linspace(0, np.pi, 100) |
| 87 | +threshold_radius = 0.5 + 0.12 * (len(set(p["row"] for p in positions)) / 2) |
| 88 | +fig.add_trace( |
| 89 | + go.Scatter( |
| 90 | + x=threshold_radius * np.cos(threshold_angle), |
| 91 | + y=threshold_radius * np.sin(threshold_angle), |
| 92 | + mode="lines", |
| 93 | + line=dict(color="rgba(0,0,0,0.3)", width=2, dash="dash"), |
| 94 | + name=f"Majority ({majority_threshold})", |
| 95 | + hoverinfo="skip", |
| 96 | + ) |
| 97 | +) |
| 98 | + |
| 99 | +# Layout |
| 100 | +fig.update_layout( |
| 101 | + title=dict( |
| 102 | + text="parliament-basic · plotly · pyplots.ai", font=dict(size=28, color="#333"), x=0.5, xanchor="center" |
| 103 | + ), |
| 104 | + xaxis=dict(showgrid=False, zeroline=False, showticklabels=False, range=[-1.3, 1.3], scaleanchor="y", scaleratio=1), |
| 105 | + yaxis=dict(showgrid=False, zeroline=False, showticklabels=False, range=[-0.15, 1.2]), |
| 106 | + legend=dict( |
| 107 | + orientation="h", yanchor="bottom", y=-0.15, xanchor="center", x=0.5, font=dict(size=16), itemsizing="constant" |
| 108 | + ), |
| 109 | + template="plotly_white", |
| 110 | + plot_bgcolor="white", |
| 111 | + paper_bgcolor="white", |
| 112 | + margin=dict(l=50, r=50, t=100, b=120), |
| 113 | +) |
| 114 | + |
| 115 | +# Add annotation for total seats |
| 116 | +fig.add_annotation( |
| 117 | + x=0, |
| 118 | + y=0.05, |
| 119 | + text=f"<b>{total_seats}</b><br>seats", |
| 120 | + font=dict(size=24, color="#333"), |
| 121 | + showarrow=False, |
| 122 | + align="center", |
| 123 | +) |
| 124 | + |
| 125 | +# Save outputs |
| 126 | +fig.write_image("plot.png", width=1600, height=900, scale=3) |
| 127 | +fig.write_html("plot.html", include_plotlyjs="cdn") |
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