添加 时长直方图q4_3b.py

时长直方图q4_3b.py

@@ -0,0 +1,17 @@
+# q4/q4_3b/q4_3b.py
+import json
+import matplotlib.pyplot as plt
+
+with open("../q2_1_crawler/movies.json", "r", encoding="utf-8") as f:
+    data = json.load(f)
+movies = data["movies"]
+durations = [m["duration"] for m in movies]
+
+# 直方图 bins=5 绿色
+plt.hist(durations, bins=5, color="green")
+plt.title("时长分布")
+plt.xlabel("时长（分钟）")
+plt.tight_layout()
+
+plt.savefig("q4_3b_hist.png", dpi=150)
+plt.show()