import redis

client = redis.Redis(host='xx.xx.xx.xx')

all_class = ['algorithm',

'computer',

'history',

'circuit_design',

'math']

def all_student():

students = client.sunion(*all_class)

return len(students)

def in_a_and_in_b(class_a, class_b):

students = client.sinter(class_a, class_b)

return len(students)

def in_a_not_in_b(class_a, class_b):

students = client.sdiff(class_a, class_b)

return len(students)

def in_a_or_in_b(class_a, class_b):

students = client.sunion(class_a, class_b)

return len(students)

if __name__ == '__main__':

print(f'当前一共有{all_student()}名学生至少选了一门课。')

print(f'当前选了math，没有选computer的学生有：{in_a_not_in_b("math", "computer")}名学生至少选了一门课。')

print(f'当前选了math，也选computer的学生有：{in_a_and_in_b("math", "computer")}名学生至少选了一门课。')

print(f'当前选了math，或者选computer的学生有：{in_a_or_in_b("math", "computer")}名学生至少选了一门课。')