+
+ +

Source code for cmlreaders.convert

+from typing import List, Optional, Tuple, Union
+import pandas as pd
+
+
+
[docs]def milliseconds_to_samples(millis: Union[int, float],
+                            sample_rate: Union[int, float]) -> int:
+    """Covert times in milliseconds to number of samples.
+
+    Parameters
+    ----------
+    millis
+        Time in ms.
+    sample_rate
+        Sample rate in samples per second.
+
+    Returns
+    -------
+    Number of samples.
+
+    """
+    return int(sample_rate * millis / 1000.)

+
+
+
[docs]def samples_to_milliseconds(samples: int,
+                            sample_rate: Union[int, float]) -> Union[int, float]:
+    """Convert samples to milliseconds.
+
+    Parameters
+    ----------
+    samples
+        Number of samples.
+    sample_rate
+        Sample rate in samples per second.
+
+    Returns
+    -------
+    Samples converted to milliseconds.
+
+    """
+    return 1000 * samples / sample_rate

+
+
+
[docs]def milliseconds_to_events(onsets: List[Union[int, float]],
+                           sample_rate: Union[int, float]) -> pd.DataFrame:
+    """Take times and produce a minimal events :class:`pd.DataFrame` to load
+    EEG data with.
+
+    Parameters
+    ----------
+    onsets
+        Onset times in ms.
+    sample_rate
+        Sample rate in samples per second.
+
+    Returns
+    -------
+    events
+        A :class:`pd.DataFrame` with ``eegoffset`` as the only column.
+
+    """
+    samples = [milliseconds_to_samples(onset, sample_rate) for onset in onsets]
+    return pd.DataFrame({"eegoffset": samples})

+
+
+
[docs]def events_to_epochs(events: pd.DataFrame, rel_start: int, rel_stop: int,
+                     sample_rate: Union[int, float],
+                     basenames: Optional[List[str]] = None
+                     ) -> List[Tuple[int, int, int]]:
+    """Convert events to epochs.
+
+    Parameters
+    ----------
+    events
+        Events to read.
+    rel_start
+        Start time relative to events in ms.
+    rel_stop
+        Stop time relative to events in ms.
+    sample_rate
+        Sample rate in Hz.
+
+    Returns
+    -------
+    epochs
+        A list of tuples giving absolute start and stop times in number of
+        samples.
+
+    """
+    rel_start = milliseconds_to_samples(rel_start, sample_rate)
+    rel_stop = milliseconds_to_samples(rel_stop, sample_rate)
+    offsets = events.eegoffset.values
+    if basenames is not None:
+        eegfiles = events.eegfile.values
+        epochs = [(offset + rel_start, offset + rel_stop,
+                   basenames.index(eegfile))
+                  for (offset, eegfile) in zip(offsets, eegfiles)]
+    else:
+        epochs = [(offset + rel_start, offset + rel_stop, 0)
+                  for offset in offsets]
+    return epochs

+
+ +
+ +