Question

import nxppy
import time

class student: # Object giving first and last name, idCard and statut
    def __init__(self, name, idCard, present):
        self.name = name
        self.idCard = idCard
        self.present = None

class_TS4 = []
class_TS4.append(student('moureton etienne', '4DC3A150', None))
class_TS4.append(student('metzinger axel', '5FG998H2', None))
# print(class_1S4)

# Instantiate reader
mifare = nxppy.Mifare()

while True:
    try:
        uid = mifare.select()
        for student in class_TS4:
            # comparing uid to the each of the student's idCard attribute
            if uid == student.idCard:
                 student.present = True
                 print(student.present)
                 print(student.name)
                 break  # since uids are unique there is no point to check other students

    # Permet le polling
    except nxppy.SelectError:
        pass

        time.sleep(1)

您好，世界！我需要您的帮助，以最快的速度……我在Hihg School的一个项目中工作，但被阻止了。我从 Python 开始，然后在运行Raspbian的Pi3 B +上进行编程。

我必须阅读某些NFC卡的 UID ，并且该卡工作正常。但是我必须检查我读取的UID是否与我的课程之一的“ self.idCard” 相匹配。如果是，我想将包含UID的对象的“ self.present” 更改为True。

至少，我的目标是像这样增加30名“学生”，并且程序可以告诉我哪个人通过了他的卡。

idCard的UID对于每个学生而言都是唯一且恒定的。

感谢所有<3

Answer 1

您当前将读取的uid与类的实例进行比较，该实例将始终为False。您应该将苹果与苹果进行比较：

while True:
    uid = mifare.select()
    for student in class_TS4:
        # comparing uid to each of the student's idCard attribute
        if uid == student.idCard:
             student.present = True
             break  # since uids are unique there is no point to check other students

另一种更有效的方法是使用字典。这样，uid查找将为O(1)：

uids_to_student = {student.idCard: student for student in class_TS4}

while True:
    # Read UID data
    uid = mifare.select()
    try:
        uids_to_student[uid].present = True
    except KeyError:
        print('No student with this UID exist in class')

顺便说一句，student.__init__接受一个present参数，但不做任何事情。从签名中删除它，使用它或给它一个默认值：

class student:
    def __init__(self, name, idCard, present=None):
        self.name = name
        self.idCard = idCard
        self.present = present

检查列表中的类/对象的属性

1 个答案: