first draft

course2/sem3/labs/lab3.01/scripts/5.py

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+from pathlib import Path
+from typing import List, Tuple
+
+import matplotlib.pyplot as plt
+
+
+def read_points(filename: str) -> List[Tuple[float, float, float]]:
+    pts = []
+    for line in Path(filename).read_text(encoding="utf-8").splitlines():
+        line = line.strip()
+        if not line or line.startswith("#"):
+            continue
+        parts = line.split()
+        if len(parts) < 3:
+            continue
+        x = float(parts[0])
+        y = float(parts[1])
+        phi = float(parts[2])
+        pts.append((x, y, phi))
+    return pts
+
+
+def phi_vs_x_at_y(
+    points: List[Tuple[float, float, float]], y_target: float, tol: float = 1e-6
+):
+    xs = []
+    phis = []
+    for x, y, phi in points:
+        if abs(y - y_target) <= tol:
+            xs.append(x)
+            phis.append(phi)
+    paired = sorted(zip(xs, phis), key=lambda p: p[0])
+    if not paired:
+        return [], []
+    xs_sorted, phis_sorted = zip(*paired)
+    return list(xs_sorted), list(phis_sorted)
+
+
+p1 = read_points("points1.txt")
+p2 = read_points("points2.txt")
+
+x1, yphi1 = phi_vs_x_at_y(p1, 10.0)
+x2, yphi2 = phi_vs_x_at_y(p2, 10.0)
+
+plt.figure(figsize=(10, 5))
+if x1:
+    plt.plot(x1, yphi1, marker="o", linestyle="-", label="points1.txt (Y=10)")
+if x2:
+    plt.plot(x2, yphi2, marker="s", linestyle="--", label="points2.txt (Y=10)")
+plt.xlabel("X (см)")
+plt.ylabel("φ (В)")
+plt.title("Зависимость φ = φ(X) при Y = 10 см")
+plt.grid(alpha=0.4)
+plt.legend()
+plt.savefig("phi_vs_x_Y10.png", dpi=300)