preData: The pre-dose metabolites dataset (data frame)
Description
The example data of pre-dose metabolites,which can be an input argument of GetDiffData,GetEndoand DataPre.The first row should be column names. The first row of the data frame should be the gender information.The second row of the data frame should be the group information.The format of group number should be "0"(pre-dose). The third row of the data frame should be the information of timepoints.