安装

install.packages("MALDIquant")
install.packages("MALDIquantForeign")
library("MALDIquant")
library("MALDIquantForeign")

查看MALDIquant包带的数据

data(package='MALDIquant')
#Data sets in package ‘MALDIquant’:

#fiedler2009subset       Example Mass Spectra (raw)

data(fiedler2009subset)
mode(fiedler2009subset)
#[1] "list"
length(fiedler2009subset)
#[1] 16

共有16个样本

fiedler2009subset[1:2]
#$sPankreas_HB_L_061019_G10.M19.T_0209513_0020740_18
#S4 class type            : MassSpectrum                
#Number of m/z values     : 42388                       
#Range of m/z values      : 1000.015 - 9999.734         
#Range of intensity values: 5 - 101840                  
#Memory usage             : 506.359 KiB                 
#Name                     : Pankreas_HB_L_061019_G10.M19
#File                     : /data/set A - discovery #leipzig/control/Pankreas_HB_L_061019_G10/0_m19/1/1SLin/fid

#$sPankreas_HB_L_061019_G10.M20.T_0209513_0020740_18
#S4 class type            : MassSpectrum                
#Number of m/z values     : 42388                       
#Range of m/z values      : 1000.015 - 9999.734         
#Range of intensity values: 6 - 111862                  
#Memory usage             : 506.359 KiB                 
#Name                     : Pankreas_HB_L_061019_G10.M20
#File                     : /data/set A - discovery #leipzig/control/Pankreas_HB_L_061019_G10/0_m20/1/1SLin/fid

par(mfrow = c(2, 2))
plot(fiedler2009subset[[1]])
plot(fiedler2009subset[[2]])
plot(fiedler2009subset[[3]])
plot(fiedler2009subset[[4]])

标准化

减少峰的波动，克服方差均值的相互影响