python-usda documentation

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Introduction

python-usda is a fork of pygov focused on USDA’s Food Composition Database API.

It was initially created to make it easier to fetch up-to-date nutritional data for some pseudo-scientific calculations in the PseudoScience project but has been extended to provide a better coverage of the API.

Setup

pip install python-usda

Usage

python-usda provides an API client called UsdaClient that is the base to all API requests:

from usda import UsdaClient
client = UsdaClient('API_KEY')

The USDA API requires a Data.gov API key that you can get for free here.

Using the client, you can list food items:

foods_list = client.list_foods(5)
for _ in range(5):
    food_item = next(foods_list)
    print(food_item.name)

Be careful; the 5 argument in the list_foods method only sets the amount of items that are returned at once; requesting one more will perform a request for another page of 5 results.

Instead of just listing food items, it is possible to perform a text search:

foods_search = client.search_foods(
     'coffee, instant, regular, prepared with water', 1)

coffee = next(foods_search)
print(coffee)

The above code will output:

Food ID 14215 'Beverages, coffee, instant, regular, prepared with water'

We can then use this food item’s ID to request a Food Report:

report = client.get_food_report(coffee.id)
for nutrient in report.nutrients:
     print(nutrient.name, nutrient.value, nutrient.unit)

The above code will output:

Water 99.09 g
Energy 2.0 kcal
Protein 0.1 g
[...]
Cholesterol 0.0 mg
Caffeine 26.0 mg

And there it is, your first nutritional information report.

There is more available than mere food items and nutritional facts; head over to the API Guide to learn more.

Error handling

The API client uses requests to perform requests to USDA’s API and does not explicitly handle its errors to let this library’s users deal with network-related errors.

As the API has a very inconsistent way of returning errors, it cannot be fully guaranteed that all API errors are properly handled. If you encounter a case of an unhandled error response from the API, please file an issue.

All API errors are subclasses of usda.base.DataGovApiError.

When an invalid API key is supplied, any API requests may raise a usda.base.DataGovInvalidApiKeyError.

When the allowed requests limit has been reached, a usda.base.DataGovApiRateExceededError is raised.

Raw results

If you prefer to receive the raw JSON data instead of classes, append _raw to any client request method. For example, to retrieve the raw JSON data for a foods list requests, use client.list_foods_raw. Those raw methods will pass all keyword arguments as parameters in the request URL.