如何在python中访问numpy结构数组中的多个列值?

我创建了一个结构化数组,如下所示:

name = ['Alice', 'Beth', 'Cathy', 'Dorothy']
studentid = [1,2,3,4]
score = [85.4, 90.4, 87.66, 78.9]
student_data = np.zeros(4, dtype={'names':('name', 'studentId', 'score'), 
                         'formats':('U10', 'i4', 'f8')})
student_data['name'] = name
student_data['studentId'] = studentid
student_data['score']=score

student_data[student_data['score'] > 85]['name']

但是,如果我试图检索另一个列和“name”,就会得到一个错误:

IndexError: only integers, slices (`:`), ellipsis (`...`), numpy.newaxis (`None`) and integer or boolean arrays are valid indices

例如,我尝试了以下方法:

student_data[student_data['score'] < 90]['name','studentid']
student_data[student_data['score'] < 90]['name']['studentid']

两者都会导致错误:

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-189-7ad7c151f0e3> in <module>
----> 1 student_data[student_data['score'] < 90]['name']['studentid']

IndexError: only integers, slices (`:`), ellipsis (`...`), numpy.newaxis (`None`) and integer or boolean arrays are valid indices

有人能告诉我我在这里犯了什么错误吗?我怎样才能有条件地检索多个列?