擅长:python、mysql、java
<p>遵循您的模式:</p>
<pre><code>notifications = DeviceNotification.objects.all()
for n in notifications:
time_period = n.time_period
logs = DeviceLog.objects.all()[:time_period]
for l in logs:
print(l.celsius)
</code></pre>
<p>我把它改成:</p>
<pre><code>logs = DeviceLog.objects.all()
log_now = logs[datetime.datetime.now()].celsius
log_pre = logs[datetime.datetime.now() - 5].celsius
dif = log_now - log_pre
if (dif) >=0:
print ("increased: ",dif,"in 5 hours")
else:
print ("decreased: ",dif,"in 5 hours")
</code></pre>