def get_median_values(data,ds):
	"""extracts median abundance values

	:param data: PTCF
	:param ds: data set identifier (ds1 or ds1)

	:return: median values of given data set 
	"""

	values = data[[x for x in list(data) if x.startswith(ds) & (x!="ds1_cluster") & (x!="ds2_cluster") & (x!="gene")]]

	return values.median(axis=1)