# Slots

**Slots are your bot’s memory.** They act as a key-value store which can be used to store information the user provided (e.g their home city) as well as information gathered about the outside world (e.g. the result of a database query).

Most of the time, you want slots to influence how the dialogue progresses. There are different slot types for different behaviors.

For example, if your user has provided their home city, you might have a `text` slot called `home_city`. If the user asks for the weather, and you _don’t_ know their home city, you will have to ask them for it. A `text` slot only tells Rasa Core whether the slot has a value. The specific value of a `text` slot (e.g. Bangalore or New York or Hong Kong) doesn’t make any difference.

If the value itself is important, use a `categorical` or a `bool` slot. There are also `float`, and `list` slots. If you just want to store some data, but don’t want it to affect the flow of the conversation, use an `unfeaturized` slot.

## [How Rasa Uses Slots](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id4)

The `Policy` doesn’t have access to the value of your slots. It receives a featurized representation. As mentioned above, for a `text` slot the value is irrelevant. The policy just sees a `1` or `0` depending on whether it is set.

**You should choose your slot types carefully!**

## [How Slots Get Set](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id5)

You can provide an initial value for a slot in your domain file:

slots:
      name:
        type: text
        initial_value: "human"

There are multiple ways that slots are set during a conversation:

### [Slots Set from NLU](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id6)

If your NLU model picks up an entity, and your domain contains a slot with the same name, the slot will be set automatically. For example:

```
# story_01
* greet{"name": "Ali"}
  - slot{"name": "Ali"}
  - utter_greet
```

In this case, you don’t have to include the `- slot{}` part in the story because it is automatically picked up.

To disable this behavior for a particular slot, you can set the `auto_fill` attribute to `False` in the domain file:

```
slots:
  name:
    type: text
    auto_fill: False
```

### [Slots Set By Clicking Buttons](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id7)

You can use buttons as a shortcut. Rasa Core will send messages starting with a `/` to the `RegexInterpreter`, which expects NLU input in the same format as in story files, e.g. `/choose{"color": "blue"}` and `/choose{"color": "red"}`.

### [Slots Set by Actions](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id8)

The second option is to set slots by returning events in [custom actions](https://legacy-docs-v1.rasa.com/1.8.2/core/actions/#custom-actions). In this case, your stories need to include the slots.

## [Slot Types](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id9)

### [Text Slot](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id10)

`text`

Use For   
User preferences where you only care whether or not they’ve been specified.

Example:

```
slots:
   cuisine:
      type: text
```

### [Boolean Slot](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id11)

`bool`

Use For  
True or False

Example:

```
slots:
   is_authenticated:
      type: bool
```

### [Categorical Slot](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id12)

`categorical`

Use For  
Slots which can take one of N values

Example:

```
slots:
   risk_level:
      type: categorical
      values:
      - low
      - medium
      - high
```

### [Float Slot](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id13)

`float`

Use For  
Continuous values

Example:

```
slots:
   temperature:
      type: float
      min_value: -100.0
      max_value:  100.0
```

### [List Slot](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id14)

`list`

Use For  
Lists of values

Example:

```
slots:
   shopping_items:
      type: list
```

### [Unfeaturized Slot](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id15)

`unfeaturized`

Use For  
Data you want to store which shouldn’t influence the dialogue flow

Example:

```
slots:
   internal_user_id:
      type: unfeaturized
```

### [Custom Slot Types](https://legacy-docs-v1.rasa.com/1.8.2/core/slots/#id16)

In the code below, we define a slot class called `NumberOfPeopleSlot`. The featurization defines how the value of this slot gets converted to a vector to our machine learning model can deal with.