> ## Documentation Index
> Fetch the complete documentation index at: https://www.getmaxim.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# isValidDate

> Validates if a string matches supported date formats and is a valid calendar date.

## Input

* **`input`**: The original input text or data
* **`output`**: The date string to validate
* **`expectedOutput`**: The expected output to compare against.

<Note>
  - Any of the input variables (`input`, `output`, `expectedOutput`) can be marked as optional.
  - The returned value from the `validate` function can be a boolean, string, or a number.
</Note>

## Output

* **`Result`**: Boolean (`true` or `false`) | string | number

## Interpretation

> Assuming this evaluator returns a boolean

* **true**: The string is a valid date
* **false**: The string is not a valid date

<Note>This evaluator requires a function named <code>validate</code>.</Note>

## Example

```python theme={null}
from datetime import datetime

def validate(input, output, expectedOutput):
    date_str = str(output)
    formats = [
        '%Y-%m-%d', '%m/%d/%Y', '%d/%m/%Y', '%Y/%m/%d', '%Y-%d-%m'
    ]
    for fmt in formats:
        try:
            datetime.strptime(date_str, fmt)
            return True
        except ValueError:
            continue
    return False
```