python - if else 在 for 循环下工作 != but ==

Question

我不明白为什么 == 条件不起作用，但 != 在 for 循环中起作用。这是代码段:

# this way it's not working . only single time running and not giving desired output

list_of_student= []

for student in student_list:

    student_detail = student(val[1],val[2],val[3])  # namedtuple

    if (student_id and student_id==student.id) or (student_name and student_name==student.name):
        return student_detail
    else:
        list_of_student.append(student_detail)

但是如果我将 == 更改为 != 并恢复以下操作，它就可以正常工作。 你能告诉我原因，或者我错在哪里吗？

#this way it's working fine.
list_of_student= []

for student in student_list:

    student_detail = student(val[1],val[2],val[3])   # namedtuple
    if (student_id and student_id!=student.id) or (student_name and student_name!=student.name):
        list_of_student.append(student_detail)

    else:
        return student_detail

Answer 1

要反转条件的逻辑，您还需要将 and and 替换为 or ，反之亦然，以及否定任何 bool 检查，此外反转比较运算符:

if ((not student_id) or student_id != student.id) and ((not student_name) or student_name != student.name):