How do I filter out duplicate alerts as in example results from python script shown below?

[ckolovson]

import requests
from datetime import datetime
URL = 'https://api.weather.gov/alerts/active?area=CA'
response = requests.get(URL)
alerts = response.json()['features']

print(f'There are {len(alerts)} active alerts.')
There are 8 active alerts.

for alert in alerts:
... expireTime = datetime.fromisoformat(alert['properties']['expires'])
... print(f"{alert['properties']['event']} for {alert['properties']['areaDesc']} till {expireTime.strftime('%A, %B %d, %Y at %I:%M %p %Z')}")
... print()
...
Air Stagnation Advisory for Western Siskiyou County; Central Siskiyou County; Northeast Siskiyou and Northwest Modoc Counties; Modoc County; Central Douglas County; Eastern Curry County and Josephine County; Eastern Douglas County Foothills; Jackson County; Siskiyou Mountains and Southern Oregon Cascades; Klamath Basin; Northern and Eastern Klamath County and Western Lake County; Central and Eastern Lake County till Thursday, November 30, 2023 at 08:00 AM UTC-08:00

Air Stagnation Advisory for Western Siskiyou County; Central Siskiyou County; Northeast Siskiyou and Northwest Modoc Counties; Modoc County; Eastern Curry County and Josephine County; Eastern Douglas County Foothills; Jackson County; Siskiyou Mountains and Southern Oregon Cascades; Klamath Basin; Northern and Eastern Klamath County and Western Lake County; Central and Eastern Lake County till Tuesday, November 28, 2023 at 05:45 PM UTC-08:00

Freeze Warning for Los Banos - Dos Palos; Merced - Madera - Mendota; Planada - Le Grand - Snelling; West Side of Fresno and Kings Counties; Caruthers - San Joaquin - Selma; Buttonwillow - Lost Hills - I5; Delano-Wasco-Shafter; Hanford - Corcoran - Lemoore; Visalia - Porterville - Reedley; Southeast San Joaquin Valley; Indian Wells Valley; Mojave Desert till Monday, November 27, 2023 at 05:45 PM UTC-08:00

Air Stagnation Advisory for Western Siskiyou County; Central Siskiyou County; Northeast Siskiyou and Northwest Modoc Counties; Modoc County; Central Douglas County; Eastern Curry County and Josephine County; Eastern Douglas County Foothills; Jackson County; Siskiyou Mountains and Southern Oregon Cascades; Klamath Basin; Northern and Eastern Klamath County and Western Lake County; Central and Eastern Lake County till Monday, November 27, 2023 at 09:00 AM UTC-08:00

Freeze Warning for Los Banos - Dos Palos; Merced - Madera - Mendota; Planada - Le Grand - Snelling; West Side of Fresno and Kings Counties; Caruthers - San Joaquin - Selma; Buttonwillow - Lost Hills - I5; Delano-Wasco-Shafter; Hanford - Corcoran - Lemoore; Visalia - Porterville - Reedley; Southeast San Joaquin Valley; Indian Wells Valley; Mojave Desert till Sunday, November 26, 2023 at 06:00 PM UTC-08:00

Freeze Watch for Los Banos - Dos Palos; Merced - Madera - Mendota; Planada - Le Grand - Snelling; West Side of Fresno and Kings Counties; Caruthers - San Joaquin - Selma; Buttonwillow - Lost Hills - I5; Delano-Wasco-Shafter; Hanford - Corcoran - Lemoore; Visalia - Porterville - Reedley; Southeast San Joaquin Valley; Indian Wells Valley; Mojave Desert till Friday, November 24, 2023 at 03:39 AM UTC-08:00

Freeze Warning for Los Banos - Dos Palos; Merced - Madera - Mendota; Planada - Le Grand - Snelling; West Side of Fresno and Kings Counties; Caruthers - San Joaquin - Selma; Buttonwillow - Lost Hills - I5; Delano-Wasco-Shafter; Hanford - Corcoran - Lemoore; Visalia - Porterville - Reedley; Southeast San Joaquin Valley; Indian Wells Valley; Mojave Desert till Friday, November 24, 2023 at 03:00 PM UTC-08:00

Freeze Watch for Los Banos - Dos Palos; Merced - Madera - Mendota; Planada - Le Grand - Snelling; West Side of Fresno and Kings Counties; Caruthers - San Joaquin - Selma; Buttonwillow - Lost Hills - I5; Delano-Wasco-Shafter; Hanford - Corcoran - Lemoore; Visalia - Porterville - Reedley; Southeast San Joaquin Valley; Indian Wells Valley; Mojave Desert till Friday, November 24, 2023 at 03:00 AM UTC-08:00

[ckolovson]

This script seems to require a check for expired alerts. However, I'm told that this is still wrong because it is filtering based on "product expiration" instead of "event expiration". Can someone please provide an example of a correct solution that filters out duplicates?

import requests
import pytz
from datetime import datetime
from pytz import timezone

URL = 'https://api.weather.gov/alerts/active?area=CA'
response = requests.get(URL)
alerts = response.json()['features']

print(f'There are {len(alerts)} active alerts.') # includes expired ones

for alert in alerts:
    expireTime = datetime.fromisoformat(alert['properties']['expires'])
    if expireTime > datetime.now(pytz.utc):
         print(f"{alert['properties']['event']} for {alert['properties']['areaDesc']} till {expireTime.strftime('%A, %B %d, %Y at %I:%M %p %Z')}")
         print()

[ckolovson]

Discussion moved to #678.