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Spectral similarity and compound identification for metabolomics. Use for comparing mass spectra, computing similarity scores (cosine, modified cosine), and identifying unknown compounds from spectral libraries. Best for metabolite identification, spectral matching, library searching. For full LC-MS/MS proteomics pipelines use pyopenms.
npx skill4agent add k-dense-ai/claude-scientific-skills matchmsfrom matchms.importing import load_from_mgf, load_from_mzml, load_from_msp, load_from_json
from matchms.exporting import save_as_mgf, save_as_msp, save_as_json
# Import spectra
spectra = list(load_from_mgf("spectra.mgf"))
spectra = list(load_from_mzml("data.mzML"))
spectra = list(load_from_msp("library.msp"))
# Export processed spectra
save_as_mgf(spectra, "output.mgf")
save_as_json(spectra, "output.json")references/importing_exporting.mdfrom matchms.filtering import default_filters, normalize_intensities
from matchms.filtering import select_by_relative_intensity, require_minimum_number_of_peaks
# Apply default metadata harmonization filters
spectrum = default_filters(spectrum)
# Normalize peak intensities
spectrum = normalize_intensities(spectrum)
# Filter peaks by relative intensity
spectrum = select_by_relative_intensity(spectrum, intensity_from=0.01, intensity_to=1.0)
# Require minimum peaks
spectrum = require_minimum_number_of_peaks(spectrum, n_required=5)references/filtering.mdfrom matchms import calculate_scores
from matchms.similarity import CosineGreedy, ModifiedCosine, CosineHungarian
# Calculate cosine similarity (fast, greedy algorithm)
scores = calculate_scores(references=library_spectra,
queries=query_spectra,
similarity_function=CosineGreedy())
# Calculate modified cosine (accounts for precursor m/z differences)
scores = calculate_scores(references=library_spectra,
queries=query_spectra,
similarity_function=ModifiedCosine(tolerance=0.1))
# Get best matches
best_matches = scores.scores_by_query(query_spectra[0], sort=True)[:10]references/similarity.mdfrom matchms import SpectrumProcessor
from matchms.filtering import default_filters, normalize_intensities
from matchms.filtering import select_by_relative_intensity, remove_peaks_around_precursor_mz
# Define a processing pipeline
processor = SpectrumProcessor([
default_filters,
normalize_intensities,
lambda s: select_by_relative_intensity(s, intensity_from=0.01),
lambda s: remove_peaks_around_precursor_mz(s, mz_tolerance=17)
])
# Apply to all spectra
processed_spectra = [processor(s) for s in spectra]Spectrumfrom matchms import Spectrum
import numpy as np
# Create a spectrum
mz = np.array([100.0, 150.0, 200.0, 250.0])
intensities = np.array([0.1, 0.5, 0.9, 0.3])
metadata = {"precursor_mz": 250.5, "ionmode": "positive"}
spectrum = Spectrum(mz=mz, intensities=intensities, metadata=metadata)
# Access spectrum properties
print(spectrum.peaks.mz) # m/z values
print(spectrum.peaks.intensities) # Intensity values
print(spectrum.get("precursor_mz")) # Metadata field
# Visualize spectra
spectrum.plot()
spectrum.plot_against(reference_spectrum)# Metadata is automatically harmonized
spectrum.set("Precursor_mz", 250.5) # Gets harmonized to lowercase key
print(spectrum.get("precursor_mz")) # Returns 250.5
# Derive chemical information
from matchms.filtering import derive_inchi_from_smiles, derive_inchikey_from_inchi
from matchms.filtering import add_fingerprint
spectrum = derive_inchi_from_smiles(spectrum)
spectrum = derive_inchikey_from_inchi(spectrum)
spectrum = add_fingerprint(spectrum, fingerprint_type="morgan", nbits=2048)references/workflows.mduv pip install matchmsuv pip install matchms[chemistry]references/filtering.mdsimilarity.mdimporting_exporting.mdworkflows.md