try to fix error: $ operator is invalid for atomic vectors  not sure why it happends?
try to fix error: $ operator is invalid for atomic vectors  not sure why it happends?

xieguigang/MassSpectrum-toolkits,xieguigang/MassSpectrum-toolkits,xieguigang/spectrum,xieguigang/spectrum,xieguigang/MassSpectrum-toolkits,xieguigang/MassSpectrum-toolkits