完成 q4_2 散点图

q4/q4_2/q4_2.py

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+# q4_2.py
+import json
+import matplotlib.pyplot as plt
+
+# 1. 读取文件
+with open("movies.json", "r", encoding="utf-8") as f:
+    data = json.load(f)
+
+# 2. 安全提取电影列表
+if type(data) is dict and "movies" in data:
+    movies = data["movies"]
+else:
+    movies = []
+
+# 3. 准备数据
+x_data = []
+y_data = []
+
+for item in movies:
+    # 这一行彻底防止报错
+    if type(item) is dict:
+        x_data.append(item["duration"])
+        y_data.append(item["rating"])
+
+# 4. 画图（题目全部要求）
+plt.scatter(x_data, y_data, color="red", alpha=0.6)
+plt.title("时长与评分关系散点图")
+plt.xlabel("时长（分钟）")
+plt.ylabel("评分")
+plt.savefig("q4_2_scatter.png", dpi=150)
+plt.close()
+
+print("运行成功！")