Question: **I attempt to connect to a RabbitMQ cluster (AMQP 1.0 plugin enabled) with a Qpid JMS 0.48.0 client and with SSL enabled, using a failover URI.**

This does not work:

```
failover:(amqps://host1:5671?transport.verifyHost=false,amqps://host2:5671?transport.verifyHost=false,amqps://host3:5671?transport.verifyHost=false)

```

But this works (without SSL):

```
failover:(amqp://host1:5672,amqp://host2:5672,amqp://host3:5672)

```

SSL is well configured, as this works:

```
amqps://host1:5671?transport.verifyHost=false

```

No error message on standard output, no logs.

I get exactly the same behavior when connecting to an Artemis cluster.

Also, I have no problem using multiple URIs with SSL from a Qpid Proton client in Python:

```
server_addr = ['amqps://host1:5671', 'amqps://host2:5671', 'amqps://host3:5671']

```

Can you please tell me what's going on?

Answer: 
You can do `groupby` and then `agg`:

```
df.groupby('Genre', sort=False).agg(lambda x: list(set(x))).reset_index()

```

and you'll get

```
      Genre  Rating CustomRating
0  Thriller     [5]          [5]
1    Comedy     [9]          [9]
2    Action  [2, 3]       [6, 7]

```
No, there is none by default. You can use `groupby` followed by an `agg` and create a `list` as suggested by others. However, there is a good reason this is discouraged ;)

Your second DataFrame is extemely difficult to work with. You can never now whether it contains a single value or a list. This goes against the whole idea of a DataFrame. Also you loose information. How many action movies where there? Did the custom rating 6 have a rating of 2 or 3. You can't answer these questions anymore. What would you do next? Calculate a summary statistic? Then just directly use `groupby().mean()`, `groupby().std()` or whatever you need? Plot that? There even is a `groupby().plot()`. 

If you are tempted to do something like that, that is a telltale sign you should think about why you need that. The general pattern in pandas is called split-apply-combine. You are trying to only do the split part. I advice you to only to do that when you have a very good reason to do so.