This function plots the zeros distributions in cells and removes genes without a certain fraction of 0 in the samples
filterZeros(file, threshold = 0, sep)
a character string indicating the path of the cells un-normalized expression counts table
a number from 0 to 1 indicating the fraction of max accepted zeros in each gene. 0 is set as default and it eliminates only genes having 0 in all cells.
separator used in count file, e.g. '\t', ','
a PDF providing zeros distributions before removal of all genes without a certain fraction of 0 in the samples. A file with the prefix *filtered* in which the filtered data are saved.