Method crop

mne/io/base.py:1571–1703

Crop raw data file. Limit the data from the raw file to go between specific times. Note that the new ``tmin`` is assumed to be ``t=0`` for all subsequently called functions (e.g., :meth:`~mne.io.Raw.time_as_index`, or :class:`~mne.Epochs`). New :term:`first_samp` and

(
        self,
        tmin=0.0,
        tmax=None,
        include_tmax=True,
        *,
        reset_first_samp=False,
        verbose=None,
    )

    @verbose
    def crop(
        self,
        tmin=0.0,
        tmax=None,
        include_tmax=True,
        *,
        reset_first_samp=False,
        verbose=None,
    ):
        """Crop raw data file.

        Limit the data from the raw file to go between specific times. Note
        that the new ``tmin`` is assumed to be ``t=0`` for all subsequently
        called functions (e.g., :meth:`~mne.io.Raw.time_as_index`, or
        :class:`~mne.Epochs`). New :term:`first_samp` and :term:`last_samp`
        are set accordingly.

        Thus function operates in-place on the instance.
        Use :meth:`mne.io.Raw.copy` if operation on a copy is desired.

        Parameters
        ----------
        %(tmin_raw)s
        %(tmax_raw)s
        %(include_tmax)s
        reset_first_samp : bool
            If True, reset :term:`first_samp` to 0 after cropping, treating
            the cropped segment as an independent recording. Note that this
            can break things if you extracted events before cropping and try
            to use them afterward. Default is False.

            .. versionadded:: 1.12
        %(verbose)s

        Returns
        -------
        raw : instance of Raw
            The cropped raw object, modified in-place.

        Notes
        -----
        After cropping, :term:`first_samp` is updated to reflect the new
        start of the data, preserving the original recording timeline.
        This means ``raw.times`` will still start at ``0.0``, but
        ``raw.first_samp`` will reflect the offset from the original
        recording. If you want to treat the cropped segment as an
        independent signal with ``first_samp=0``, you can convert it
        to a :class:`~mne.io.RawArray`::

            raw_array = mne.io.RawArray(raw.get_data(), raw.info)

        Examples
        --------
        By default, cropping preserves the original recording timeline,
        so :term:`first_samp` remains non-zero after cropping::

            >>> raw = mne.io.read_raw_fif(fname)  # doctest: +SKIP
            >>> print(raw.first_samp)  # doctest: +SKIP