matchms.Spectrum module

class matchms.Spectrum.Spectrum(mz: numpy.array, intensities: numpy.array, metadata: Optional[dict] = None)

Bases: object

Container for a collection of peaks, losses and metadata

For example

import numpy as np
from matchms import Scores, Spectrum
from matchms.similarity import CosineGreedy

spectrum = Spectrum(mz=np.array([100, 150, 200.]),
                      intensities=np.array([0.7, 0.2, 0.1]),
                      metadata={'id': 'spectrum1',
                                "peak_comments": {200.: "the peak at 200 m/z"}})

print(spectrum.peaks.mz[0])
print(spectrum.peaks.intensities[0])
print(spectrum.get('id'))
print(spectrum.peak_comments.get(200))

Should output

100.0
0.7
spectrum1
the peak at 200 m/z

peaks

Peaks of spectrum

Type

Spikes

losses

Losses of spectrum, the difference between the precursor and all peaks.

Can be filled with

from matchms import Spikes
spectrum.losess = Spikes(mz=np.array([50.]), intensities=np.array([0.1]))

Type

Spikes or None

metadata

Dict of metadata with for example the scan number of precursor m/z.

Type

dict

__init__(mz: numpy.array, intensities: numpy.array, metadata: Optional[dict] = None)

Parameters

• mz – Array of m/z for the peaks

• intensities – Array of intensities for the peaks

• metadata – Dictionary with for example the scan number of precursor m/z.

clone()

Return a deepcopy of the spectrum instance.

get(key: str, default=None)

Retrieve value from metadata dict. Shorthand for

val = self.metadata[key]

metadata_hash()

Return a (truncated) sha256-based hash which is generated based on the spectrum metadata. Spectra with same metadata results in same metadata_hash.

plot(figsize=(8, 6), dpi=200, **kwargs)

Plot to visually inspect a spectrum run spectrum.plot()

Example of a spectrum plotted using spectrum.plot() ..

plot_against(other_spectrum, figsize=(8, 6), dpi=200, **spectrum_kws)

Compare two spectra visually in a mirror plot.

To visually compare the peaks of two spectra run spectrum.plot_against(other_spectrum)

Example of a mirror plot comparing two spectra spectrum.plot_against() ..

set(key: str, value)

Set value in metadata dict. Shorthand for

self.metadata[key] = val

spectrum_hash()

Return a (truncated) sha256-based hash which is generated based on the spectrum peaks (mz:intensity pairs). Spectra with same peaks will results in same spectrum_hash.