Python选择基于内部函数的变量

Question

我正在尝试创建可以从 API 库中提取信息的函数，但我很难弄清楚如何将变量选择传递给函数而不被读取为值。

代码示例：

def get_list(api, val = None):
    response =[]
    list = api
    for i in list:
        response.append(f'i.{val}')
    return (response)


devices = get_list(api.devices.all(), 'name')

print(devices )

给我一长串“i.name”

我需要解决我的名字作为变量选择而不是实际值

我累了：

response.append(vars()[f'i.{val}']) # locals(), globals()

但我收到错误：“KeyError：'i.name'”

我认为问题在于“i.name”并没有真正作为函数中的变量存在。

Answer 1

当您使用设备调用此函数时，您将参数“名称”作为“val”传递，然后您将其循环并附加到结果中。

如果您还可以在此处包含您想要的结果，那将很有帮助，因为目前还不清楚。

Answer 2

我正在使用 LibremsAPI 库从 LibreNMS 读取数据

常规 GET 请求如下所示：

ip_list []
for device in lnms.devices.all():
    ip_list.append(device.ip)

name_list []
for device in lnms.devices.all():
    ip_list.append(device.sysName)

因此，为了不必对我需要的 api 请求进行每一个变体，我们的想法是有一个“列表”函数。

Answer 3

据我了解，您想编写一个函数，这样您就不必重复for

ip_list = []
for device in lnms.devices.all():
    ip_list.append(device.ip)

name_list = []
for device in lnms.devices.all():
    ip_list.append(device.sysName)

首先，在您的代码中，您使用 list 作为变量，您不应该导致 list 是一个内置关键字。

This comment 解释了为什么您的代码不起作用

这就是它的工作方式

def get_data(devices, key):
    response = []
    for device in devices:
        response.append(device[key])
    return response

甚至更短的使用list comprehension

def get_data(devices, key):
    return [device[key] for device in devices]

然后你可以做

ip_list = []
ip_list = get_data(lnms.devices.all(), 'ip')

name_list = []
name_list = get_data(lnms.devices.all(), 'sysName')

如果你不想重复lnms.devices.all() 您可以编写如下函数

def get_data_from_devices(key):
    response = []
    for device in lnms.devices.all():
        response.append(device[key])
    return response

或者使用列表理解

def get_data_from_devices(key):
    return [device[key] for device in lnms.devices.all()]

然后你会称它们为

ip_list = []
ip_list = get_data_from_devices('ip')

name_list = []
name_list = get_data_from_devices('sysName')

PS：需要更好的函数名称

Answer 4

我是 Python 的新手，从上面的文字中可以看出我没有很好地解释自己，所以这是我试图让事情更清楚的尝试。

命令“lnms_device_names = get_data(lnms.devices.all(), 'sysName')”

原始尝试：

def get_data(devices, key):
    response = []
    for device in devices:
        response.append(device.key)
    return response

# => Endpoint devices/29/key does not exists

def get_data(devices, key):
    response = []
    for device in devices:
        response.append(f'device.{key}')
    return response

# => ['device.sysName', 'device.sysName', 'device.sysName', 'device.sysName']

在此线程中使用建议失败的尝试：

def get_data(devices, key):
    return [device[key] for device in devices]

# => TypeError: 'LibreNMSEndpoint' object is not subscriptable

def get_data(devices, key):
    response = []
    for device in devices:
        response.append(device[key])
    return response

# => TypeError: 'LibreNMSEndpoint' object is not subscriptable

def get_data(devices, key):
    response = []
    for device in devices:
        response.append(f'{device}.{key}') # same result with f'{str(device)}.{key}'
    return response

# => full data dump no filtering by key

不使用任何功能时的外观

#WORKS:
lnms_device_names = []
for device in lnms.devices.all():
    lnms_device_names.append(device.sysName)

# => ['dc2-h1-ipn03', 'dc2-h1-spine1', 'dc2-h1-spine2', 'dc2-h1-leaf1']

数据结构：

{
            "device_id": 1,
            "inserted": "2022-08-15 15:50:33",
            "hostname": "172.21.142.10",
            "sysName": "dc2-h1-ipn03",
            "display": null,
            "ip": "",
            "overwrite_ip": null,
            "community": "xxxxxxx",
            "authlevel": null,
            "authname": null,
            "authpass": null,
            "authalgo": null,
            "cryptopass": null,
            "cryptoalgo": null,
            "snmpver": "v2c",
            "port": 161,
            "transport": "udp",
            "timeout": null,
            "retries": null,
            "snmp_disable": 0,
            "bgpLocalAs": 1,
            "sysObjectID": ".1.3.6.1.4.1.9.12.3.1.3.1812",
            "sysDescr": "Cisco NX-OS(tm) nxos.7.0.3.I7.9.bin, Software (nxos), Version 7.0(3)I7(9), RELEASE SOFTWARE Copyright (c) 2002-2020 by Cisco Systems, Inc. Compiled 8/27/2020 4:00:00",
            "sysContact": null,
            "version": "7.0(3)I7(9)",
            "hardware": "N9K-C93180YC-EX",
            "features": null,
            "location_id": 1,
            "os": "nxos",
            "status": 1,
            "status_reason": "",
            "ignore": 0,
            "disabled": 0,
            "uptime": 47671869,
            "agent_uptime": 0,
            "last_polled": "2022-11-02 15:28:35",
            "last_poll_attempted": null,
            "last_polled_timetaken": 8.46,
            "last_discovered_timetaken": 293.18,
            "last_discovered": "2022-11-02 12:05:18",
            "last_ping": "2022-11-02 15:31:02",
            "last_ping_timetaken": 1.83,
            "purpose": null,
            "type": "network",
            "serial": "xxxxxx",
            "icon": "cisco.svg",
            "poller_group": 0,
            "override_sysLocation": 0,
            "notes": null,
            "port_association_mode": 1,
            "max_depth": 0,
            "disable_notify": 0,
            "dependency_parent_id": null,
            "dependency_parent_hostname": null,
            "location": "xxxxx",
            "lat": 64.132453,
            "lng": -21.877419
        },
        {
            "device_id": 2,
            ....
            ....