Iterating over data
Iteration methods
There are several ways to iterate over the data messages in a FIT file:
- the 'direct' iterations over the FIT file, and interacting with the data_messages property.
The return type of the iterations is always a dict with field names as key. When interacting
with the data_messages property, you will have access to the DataMessage instances.
Direct iterate
The easiest way is to directly iterate over the decoded fitfile variable. This will
'chain' all the data messages of various types together in a single loop. The return value
will be a dict of field data.
>>> from fittie import decode
>>> fitfile = decode("/path/to/fit/file.fit")
>>> for data in fitfile:
... print(data)
{'serial_number': 1234, 'time_created': 1046114779, 'manufacturer': 260, 'type': 4}
{'timestamp': 1046119077, 'power': 204, 'heart_rate': 123, 'speed': 12500}
The first message is of type file_id, the second message is of type record.
Filtered iterate
The data messages can be filtered by message type, and optional field names, before iterating
over the fitfile. The return value will also be a dict, but will only contain
the fields that were provided in the filter.
>>> from fittie import decode
>>> fitfile = decode("/path/to/fit/file.fit")
>>> for data in fitfile(message_type="record", fields=["timestamp", "power"]):
... print(data)
{'timestamp': 1046119077, 'power': 204}
Only the messages of type record are returned, with a filter on fields timestamp and power.
Notes
If a filtered message type is not found, an empty list will be returned. If a filtered field does
not exist, it will be returned with value None.
Accessing data messages property
The parsed FIT file has a data_messages property. This is a dict with message type keys and lists of
DataMessage as values. To read the data of a DataMessage, access its fields property.
Helper methods and properties
The FIT file has a number of helper methods and properties to make interacting with this property a bit more convenient.
Get a list of all available message types
>>> fitfile.available_message_types
['file_id', 'device_info', 'event', 'record', 'lap', 'session', 'activity']
Get all messages of a specific type