textual/docs/widgets/input.md

Input

A single-line text input widget.

• Focusable
• Container

Examples

A Simple Example

The example below shows how you might create a simple form using two Input widgets.

=== "Output"

```{.textual path="docs/examples/widgets/input.py" press="D,a,r,r,e,n"}
```

=== "input.py"

```python
--8<-- "docs/examples/widgets/input.py"
```

Input Types

The Input widget supports a type parameter which will prevent the user from typing invalid characters. You can set type to any of the following values:

input.type	Description
"integer"	Restricts input to integers.
"number"	Restricts input to a floating point number.
"text"	Allow all text (no restrictions).

=== "Output"

```{.textual path="docs/examples/widgets/input_types.py" press="1234"}
```

=== "input_types.py"

```python
--8<-- "docs/examples/widgets/input_types.py"
```

If you set type to something other than "text", then the Input will apply the appropriate validator.

Restricting Input

You can limit input to particular characters by supplying the restrict parameter, which should be a regular expression. The Input widget will prevent the addition of any characters that would cause the regex to no longer match. For instance, if you wanted to limit characters to binary you could set restrict=r"[01]*".

!!! note

The `restrict` regular expression is applied to the full value and not just to the new character.

Maximum Length

You can limit the length of the input by setting max_length to a value greater than zero. This will prevent the user from typing any more characters when the maximum has been reached.

Validating Input

You can supply one or more [validators][textual.validation.Validator] to the Input widget to validate the value.

All the supplied validators will run when the value changes, the Input is submitted, or focus moves out of the Input. The values "changed", "submitted", and "blur", can be passed as an iterable to the Input parameter validate_on to request that validation occur only on the respective mesages. (See [InputValidationOn][textual.widgets._input.InputValidationOn] and [Input.validate_on][textual.widgets.Input.validate_on].) For example, the code below creates an Input widget that only gets validated when the value is submitted explicitly:

input = Input(validate_on=["submitted"])

Validation is considered to have failed if any of the validators fail.

You can check whether the validation succeeded or failed inside an [Input.Changed][textual.widgets.Input.Changed] or [Input.Submitted][textual.widgets.Input.Submitted] handler by looking at the validation_result attribute on these events.

In the example below, we show how to combine multiple validators and update the UI to tell the user why validation failed. Click the tabs to see the output for validation failures and successes.

=== "input_validation.py"

```python hl_lines="8-15 31-35 42-45 56-62"
--8<-- "docs/examples/widgets/input_validation.py"
```

1. `Number` is a built-in `Validator`. It checks that the value in the `Input` is a valid number, and optionally can check that it falls within a range.
2. `Function` lets you quickly define custom validation constraints. In this case, we check the value in the `Input` is even.
3. `Palindrome` is a custom `Validator` defined below.
4. The `Input.Changed` event has a `validation_result` attribute which contains information about the validation that occurred when the value changed.
5. Here's how we can implement a custom validator which checks if a string is a palindrome. Note how the description passed into `self.failure` corresponds to the message seen on UI.
6. Textual offers default styling for the `-invalid` CSS class (a red border), which is automatically applied to `Input` when validation fails. We can also provide custom styling for the `-valid` class, as seen here. In this case, we add a green border around the `Input` to indicate successful validation.

=== "Validation Failure"

```{.textual path="docs/examples/widgets/input_validation.py" press="-,2,3"}
```

=== "Validation Success"

```{.textual path="docs/examples/widgets/input_validation.py" press="4,4"}
```

Textual offers several [built-in validators][textual.validation] for common requirements, but you can easily roll your own by extending [Validator][textual.validation.Validator], as seen for Palindrome in the example above.

Validate Empty

If you set valid_empty=True then empty values will bypass any validators, and empty values will be considered valid.

Reactive Attributes

Name	Type	Default	Description
cursor_blink	bool	True	True if cursor blinking is enabled.
value	str	""	The value currently in the text input.
cursor_position	int	0	The index of the cursor in the value string.
placeholder	str	""	The dimmed placeholder text to display when the input is empty.
password	bool	False	True if the input should be masked.
restrict	str	None	Optional regular expression to restrict input.
type	str	"text"	The type of the input.
max_length	int	None	Maximum length of the input value.
valid_empty	bool	False	Allow empty values to bypass validation.

Messages

• [Input.Changed][textual.widgets.Input.Changed]
• [Input.Submitted][textual.widgets.Input.Submitted]

Bindings

The input widget defines the following bindings:

::: textual.widgets.Input.BINDINGS options: show_root_heading: false show_root_toc_entry: false

Component Classes

The input widget provides the following component classes:

::: textual.widgets.Input.COMPONENT_CLASSES options: show_root_heading: false show_root_toc_entry: false

Additional Notes

• The spacing around the text content is due to border. To remove it, set border: none; in your CSS.

---

::: textual.widgets.Input options: heading_level: 2