---
title: Lookup
sidebar_position: 2
---

import Tabs from "@theme/Tabs";
import TabItem from "@theme/TabItem";

Lookup an option symbol from a human-readable string format.

## Making Requests

Use the `lookup()` method on the `options` resource to lookup option symbols. The method supports multiple output formats:

| Output Format | Return Type | Description |
|---------------|-------------|-------------|
| **DATAFRAME** | `pandas.DataFrame` or `polars.DataFrame` | Returns a DataFrame with option lookup data indexed by optionSymbol (default). |
| **INTERNAL** | `OptionsLookup` or `OptionsLookupHumanReadable` | Returns an OptionsLookup object. When `use_human_readable=True`, returns an OptionsLookupHumanReadable object with capitalized field names. |
| **JSON** | `dict` | Returns the raw JSON response as a dictionary. |
| **CSV** | `str` | Writes CSV data to file and returns the filename string. |

<a name="lookup"></a>
## lookup

```python
def lookup(
    lookup: str,
    *,
    output_format: OutputFormat = OutputFormat.DATAFRAME,
    date_format: DateFormat = None,
    columns: list[str] = None,
    add_headers: bool = None,
    use_human_readable: bool = False,
    mode: Mode = None,
    filename: str | Path = None,
) -> OptionsLookup | OptionsLookupHumanReadable | dict | str | MarketDataClientErrorResult
```

Fetches option lookup data for a given lookup string. The lookup string should contain the underlying symbol, expiration date, strike price, and option side in the format: "SYMBOL DD-MM-YYYY STRIKE SIDE" (e.g., "AAPL 20-12-2024 150.0 call"). The `lookup` parameter can be passed as the first positional argument or as a keyword argument. All other parameters must be keyword-only.

#### Parameters

- `lookup` (str)

  The lookup string in the format "SYMBOL DD-MM-YYYY STRIKE SIDE" (e.g., "AAPL 20-12-2024 150.0 call").

- `output_format` ([OutputFormat](/sdk/py/settings#output-format), optional)

  The format of the returned data. Defaults to `OutputFormat.DATAFRAME`. See [Settings](/sdk/py/settings) for details.

- `date_format` ([DateFormat](/sdk/py/settings#date-format), optional)

  The date format to use in the response. Defaults to `DateFormat.UNIX`. See [Settings](/sdk/py/settings) for details.

- [`columns`](/sdk/py/settings#columns) (optional)

  Specify which columns to include in the response. See [Settings](/sdk/py/settings) for details.

- [`add_headers`](/sdk/py/settings#headers) (optional)

  Whether to include headers in the response. See [Settings](/sdk/py/settings) for details.

- [`use_human_readable`](/sdk/py/settings#human-readable) (optional)

  Whether to use human-readable format for values. Only applies when `output_format=OutputFormat.INTERNAL`. See [Settings](/sdk/py/settings) for details.

- `mode` ([Mode](/sdk/py/settings#data-mode), optional)

  The data feed mode to use. See [Settings](/sdk/py/settings) for details.

- `filename` (str | Path, optional)

  File path for CSV output (only used with `output_format=OutputFormat.CSV`).

#### Returns

- `OptionsLookup` | `OptionsLookupHumanReadable` | `dict` | `str` | `MarketDataClientErrorResult`

  The option lookup data in the requested format, or a `MarketDataClientErrorResult` if an error occurred.

#### Notes

- The lookup string format is: "SYMBOL DD-MM-YYYY STRIKE SIDE"
- Example: "AAPL 20-12-2024 150.0 call" or "AAPL 20-12-2024 150.0 put"
- When using `OutputFormat.DATAFRAME`, the DataFrame is indexed by the `optionSymbol` column.

<Tabs>
<TabItem value="Example (DataFrame)" label="Example (DataFrame)">

```python
from marketdata.client import MarketDataClient

client = MarketDataClient()

# Get option lookup as DataFrame (default)
# lookup can be passed positionally or as keyword
df = client.options.lookup("AAPL 20-12-2024 150.0 call")
# or
df = client.options.lookup(lookup="AAPL 20-12-2024 150.0 call")

print(df)
```

</TabItem>

<TabItem value="Example (Internal)" label="Example (Internal)">

```python
from marketdata.client import MarketDataClient
from marketdata.input_types.base import OutputFormat

client = MarketDataClient()

# Get option lookup as internal object
lookup_result = client.options.lookup(
    "AAPL 20-12-2024 150.0 call",
    output_format=OutputFormat.INTERNAL
)

# Access lookup properties
print(f"Option Symbol: {lookup_result.optionSymbol}")
```

</TabItem>

<TabItem value="Example (JSON)" label="Example (JSON)">

```python
from marketdata.client import MarketDataClient
from marketdata.input_types.base import OutputFormat

client = MarketDataClient()

# Get option lookup as JSON
lookup_result = client.options.lookup(
    "AAPL 20-12-2024 150.0 call",
    output_format=OutputFormat.JSON
)

print(lookup_result)
```

</TabItem>

<TabItem value="Example (CSV)" label="Example (CSV)">

```python
from marketdata.client import MarketDataClient
from marketdata.input_types.base import OutputFormat
from pathlib import Path

client = MarketDataClient()

# Get option lookup as CSV
csv_file = client.options.lookup(
    "AAPL 20-12-2024 150.0 call",
    output_format=OutputFormat.CSV,
    filename=Path("lookup.csv")
)

print(f"CSV file saved to: {csv_file}")
```

</TabItem>

<TabItem value="Example (Human Readable)" label="Example (Human Readable)">

```python
from marketdata.client import MarketDataClient
from marketdata.input_types.base import OutputFormat

client = MarketDataClient()

# Get option lookup in human-readable format
lookup_result = client.options.lookup(
    "AAPL 20-12-2024 150.0 call",
    output_format=OutputFormat.INTERNAL,
    use_human_readable=True
)

# Access lookup properties
print(f"Symbol: {lookup_result.Symbol}")
```

</TabItem>
</Tabs>

<a name="OptionsLookup"></a>
## OptionsLookup

```python
@dataclass
class OptionsLookup:
    s: str
    optionSymbol: str
```

OptionsLookup represents the result of an option symbol lookup, containing the resolved option symbol.

#### Properties

- `s` (str): Status indicator ("ok" for successful responses).
- `optionSymbol` (str): The resolved option symbol.

<a name="OptionsLookupHumanReadable"></a>
## OptionsLookupHumanReadable

```python
@dataclass
class OptionsLookupHumanReadable:
    Symbol: str
```

OptionsLookupHumanReadable represents an option symbol lookup result in human-readable format with capitalized field names.

#### Properties

- `Symbol` (str): The resolved option symbol.

#### Notes

- Field names use capitalized format (e.g., `Symbol` instead of `optionSymbol`).
