msft - - passing axis= does things row-wise instead in all casesthe data points are aligned by label before computing the correlation unique valuesvalue countsand membership another class of related methods extracts information about the values contained in one-dimensional series to illustrate theseconsider this examplein [ ]obj series([' '' '' '' '' '' '' '' '' ']the first function is uniquewhich gives you an array of the unique values in seriesin [ ]uniques obj unique(in [ ]uniques out[ ]array([cadb]dtype=objectthe unique values are not necessarily returned in sorted orderbut could be sorted after the fact if needed (uniques sort()relatedlyvalue_counts computes series containing value frequenciesin [ ]obj value_counts(out[ ] the series is sorted by value in descending order as convenience value_counts is also available as top-level pandas method that can be used with any array or sequencein [ ]pd value_counts(obj valuessort=falseout[ ] lastlyisin is responsible for vectorized set membership and can be very useful in filtering data set down to subset of values in series or column in dataframein [ ]mask obj isin([' '' ']in [ ]mask out[ ] true false false false false true true in [ ]obj[maskout[ ] summarizing and computing descriptive statistics www it-ebooks info