如何从Python字典列表中筛选出分数≥80的学生姓名？

问题描述 #

现有Python字典列表数据：

student_data = [
    {"name":"Budi", "score": 90},
    {"name":"Nina", "score": 78},
    {"name":"Rudi", "score": 91},
    {"name":"Olivia","score": 76},
    {"name":"Leo", "score": 80},
    {"name":"Liam", "score": 67},
    {"name":"Sheila","score": 76}
]

需求：获取分数≥80的学生姓名并以列表形式输出，预期结果：['Budi', 'Rudi', 'Leo']

尝试以下代码出现报错：

for i in range(len(student_data)): 
    if student_data[i].values()>=80:
        print(student_data[i].keys())

错误原因 #

1. 类型不匹配：student_data[i].values() 返回的是字典所有值的视图对象（如dict_values(['Budi', 90])），无法直接与整数80做比较，会触发类型错误
2. 取值错误：student_data[i].keys() 返回的是字典的键集合，不是学生姓名，应该通过student_data[i]['name']直接获取姓名
3. 未收集结果：原代码仅逐个打印，无法生成预期的列表格式

正确实现 #

方法1：普通循环收集结果 #

student_data = [
    {"name":"Budi", "score": 90},
    {"name":"Nina", "score": 78},
    {"name":"Rudi", "score": 91},
    {"name":"Olivia","score": 76},
    {"name":"Leo", "score": 80},
    {"name":"Liam", "score": 67},
    {"name":"Sheila","score": 76}
]

result = []
for student in student_data:
    # 直接通过键名获取分数和姓名
    if student["score"] >= 80:
        result.append(student["name"])
print(result)

方法2：列表推导式（更简洁） #

student_data = [
    {"name":"Budi", "score": 90},
    {"name":"Nina", "score": 78},
    {"name":"Rudi", "score": 91},
    {"name":"Olivia","score": 76},
    {"name":"Leo", "score": 80},
    {"name":"Liam", "score": 67},
    {"name":"Sheila","score": 76}
]

# 一行代码完成筛选和收集
result = [student["name"] for student in student_data if student["score"] >= 80]
print(result)

两种方法运行后都会输出预期结果：['Budi', 'Rudi', 'Leo']

内容的提问来源于stack exchange，提问作者Jovian Aditya