What does the "Peaks appearing in less than half the samples in each group were ignored" mean?

MetaboAnalyst
,
1

During peak picking and alignment, a valid peak group should appear in 50% of the data in at least one group in order to remain.

The underlying R code snippet:

#'@param minfrac, define the minimum fraction of samples necessary in at least one of the sample groups for
#'it to be a valid group
#'@param minsamp, define the minimum number of samples necessary in at least one of the sample groups for 
#'it to be a valid group 

# minfrac = 0.5, minsamp = 1,
….
  # test for each grouped features (i.e. a single peak before alignment) 
  # default require at least half of samples per group
     if (! any(gcount >= classnum*minfrac & gcount >= minsamp))
        next # ignore
...