Data Import

msbuddy provides functions to import data from USI (load_usi) and mgf files (load_mgf). Custom data import can be achieved by creating msbuddy.base.MetaFeature objects.

Built-in Data Import

load_usi(usi_list: str | List[str], adduct_list: None | str | List[str] = None)

Read from a single USI string or a sequence of USI strings, and load the data into the data attribute of the msbuddy.Msbuddy object. The USI string will be used as the unique identifier in msbuddy.

Parameters:

usi_list – str or List[str]. A single USI string or a sequence of USI strings.
adduct_list (optional) – str or List[str]. A single adduct string or a sequence of adduct strings, which will be applied to all USI strings accordingly.

Returns:

None. A list of msbuddy.base.MetaFeature objects will be stored in the data attribute of the msbuddy.Msbuddy object.

Example Usage:

from msbuddy import Msbuddy

# instantiate a Msbuddy object
engine = Msbuddy()

# load a single USI
engine.load_usi('mzspec:GNPS:GNPS-LIBRARY:accession:CCMSLIB00003740036')

# load a list of USIs
engine.load_usi(['mzspec:GNPS:GNPS-LIBRARY:accession:CCMSLIB00003740036',
                 'mzspec:GNPS:GNPS-LIBRARY:accession:CCMSLIB00000845027'])

# load USIs with adducts
engine.load_usi(usi_list=['mzspec:GNPS:GNPS-LIBRARY:accession:CCMSLIB00003740036',
                          'mzspec:GNPS:GNPS-LIBRARY:accession:CCMSLIB00000845027'],
                adduct_list=['[M+H]+', '[M-H2O+H]+'])

load_mgf(mgf_file: str)

Read a single mgf file, and load the data into the data attribute of the msbuddy.Msbuddy object. In mgf files, the field TITLE, SPECTRUMID or SPECTRUM_ID will be used as the unique identifier in msbuddy. Please include one of these fields in the mgf file. See demo mgf file

Parameters:: mgf_file – str. The path to the mgf file.
Returns:: None. A list of msbuddy.base.MetaFeature objects will be stored in the data attribute of the msbuddy.Msbuddy object.

Example Usage:

from msbuddy import Msbuddy

# instantiate a Msbuddy object
engine = Msbuddy()

# load a single mgf file
engine.load_mgf('input_file.mgf')

Custom Data Import

Users can also import data from custom data sources using the msbuddy.base.MetaFeature class and the msbuddy.base.Spectrum class.

We first show an example of importing an MS/MS spectrum only.

from msbuddy import Msbuddy
from msbuddy.base import MetaFeature, Spectrum
import numpy as np

# instantiate a Msbuddy object
engine = Msbuddy()

# create a Spectrum object
ms2_spec = Spectrum(mz_array = np.array([100, 200, 300]),
                    int_array = np.array([1, 2, 3]))

# create a MetaFeature object
metafeature = MetaFeature(identifier = 0,  # unique identifier for the MetaFeature object
                          mz = 400.00,  # precursor m/z
                          rt = None,  # retention time, can be None if not available
                          charge = 1,  # precursor charge
                          ms2 = ms2_spec)

# add to the Msbuddy object, List[MetaFeature] is accepted
engine.add_data([metafeature])

Note that for msbuddy.base.MetaFeature class, the identifier, mz and charge attributes are required; attributes rt, ms1 and ms2 are optional. If they are not provided, None will be assigned.

A more complicated example with both MS1 isotope pattern and MS/MS is shown below. You can also specify the adduct type.

from msbuddy import Msbuddy
from msbuddy.base import MetaFeature, Spectrum
import numpy as np

# instantiate a Msbuddy object
engine = Msbuddy()

# create a Spectrum object for MS1 isotope pattern
ms1_spec = Spectrum(mz_array = np.array([400, 401, 402]),
                    int_array = np.array([100, 20, 5]))

# create a Spectrum object for MS/MS
ms2_spec = Spectrum(mz_array = np.array([100, 200, 300]),
                    int_array = np.array([1, 2, 3]))

# create a MetaFeature object
metafeature = MetaFeature(identifier = 0,
                          mz = 400.00,
                          charge = 1,
                          adduct = '[M+H]+',
                          ms1 = ms1_spec,
                          ms2 = ms2_spec)

# add to the Msbuddy object, List[MetaFeature] is accepted
engine.add_data([metafeature])