feat: python

20-24/lianxi-switch.py

@@ -0,0 +1,119 @@
+# Python没有原生的switch-case语句，但可以通过以下几种方式来实现类似的功能：
+
+# if-elif-else结构：最直接的方法，适合简单的条件判断
+# 字典映射：推荐的方法，利用字典的键值对映射实现高效的条件分支
+# 函数字典：在字典中存储函数对象，实现复杂的逻辑处理
+# Python 3.10+ match语句：现代Python提供的模式匹配语法
+
+
+# 字典映射
+def switch_dict(case):
+    switcher = {
+        "A": "case A",
+        "B": "case B",
+        "C": "case C",
+    }
+    return switcher.get(case, "Defaule Case")
+
+
+result = switch_dict("A")
+print(result)  # case A
+result = switch_dict("D")
+print(result)  # Defaule Case
+
+
+# 使用函数字典
+def case_a():
+    return "Action for case A"
+
+
+def case_b():
+    return "Action for case B"
+
+
+def case_c():
+    return "Action for case C"
+
+
+def case_default():
+    return "Default action"
+
+
+def switch_funtion_dice(case):
+    switer = {"A": case_a, "B": case_b, "C": case_c}
+    fn = switer.get(case, case_default)
+    return fn()
+
+
+result = switch_funtion_dice("A")
+print(result)
+result = switch_funtion_dice("F")
+print(result)
+
+
+# 自 Python 3.10 起，官方引入了结构化匹配（match 语句），可以原生实现类似 switch 的多分支选择功能。match 让代码更加优雅、可读性更强，尤其适用于分支较多、需要解构或复杂条件匹配的场景。
+
+
+def switch_match(case):
+    """
+    使用 Python 3.10+ 的 match 语句实现 switch 功能
+    这是最现代和强大的方法
+    """
+    match case:
+        case "A":
+            return "Case A"
+        case "B":
+            return "Case B"
+        case "C":
+            return "Case C"
+        case _:
+            return "Default case"
+
+
+result = switch_match("A")
+print(result)
+result = switch_match("F")
+print(result)  # Default case
+
+
+# 数值范围匹配
+def grade_evaluator(sorce):
+    grade_map = {
+        range(90, 101): "A",
+        range(80, 90): "B",
+        range(70, 80): "C",
+        range(60, 70): "D",
+    }
+    for score_range, grade in grade_map.items():
+        if sorce in score_range:
+            return grade
+
+    return "F"
+
+
+# 测试成绩评估
+scores = [
+    {"scorce": 95},
+    {"scorce": 85},
+    {"scorce": 75},
+    {"scorce": 65},
+    {"scorce": 55},
+]
+
+for item in scores:
+    grade = grade_evaluator(item["scorce"])
+    item["grade"] = grade
+
+print(scores)
+
+
+def greet(name, msg="Hello"):
+    print(f"{msg}, {name}!")
+
+
+greet("Alice")  # 输出：Hello, Alice!
+greet("Bob", "Hi")  # 输出：Hi, Bob!
+
+
+num_enough = 10
+print(num_enough is False)