im = build_intensity_matrix_i(data) # Get the scan of a known TIC peak (at RT 31.17 minutes) # get the index of the scan nearest to 31.17 minutes (converted to seconds) scan_i = im.get_index_at_time(31.17*60.0) # get the MassSpectrum Object ms = im.get_ms_at_index(scan_i) # create a Peak object peak = Peak(31.17, ms, minutes=True) print peak.get_UID() # modify the range and null TMS ions peak.crop_mass(60, 450) peak.null_mass(73) peak.null_mass(147) # New UID after modification print peak.get_UID() # Create another peak from an isomer of the first peak (at RT 31.44 minutes) scan_i = im.get_index_at_time(31.44*60.0) ms = im.get_ms_at_index(scan_i) peak2 = Peak(31.44, ms, minutes=True) # modify the range and null TMS ions peak2.crop_mass(60, 450) peak2.null_mass(73) peak2.null_mass(147)
index = im.get_index_of_mass(73.3) print(index) # ## Modifying a Peak Object # # The Peak object has methods for modifying the mass spectrum. The mass range can # be cropped to a smaller range with |crop_mass()|, and the intensity values for # a single ion can be set to zero with |null_mass()|. For example, the mass range # can be set from 60 to 450 |m/z|, and the ions related to sample preparation can # be ignored by setting their intensities to zero as follows: # In[9]: peak.crop_mass(60, 450) peak.null_mass(73) peak.null_mass(147) # The UID is automatically updated to reflect the changes: # In[10]: print(peak.UID) # It is also possible to change the peak mass spectrum by setting the attribute |pyms.Peak.Class.Peak.mass_spectrum|.
