DataFrameGroupBy.idxmax(axis=0, skipna=True) Return index of first occurrence of maximum over requested

Series.cat.add_categories(*args, **kwargs)

DataFrame.merge(right, how='inner', on=None, left_on=None, right_on=None, left_index=False, right_index=False, sort=False, suffixes=('_x',

Series.notnull()

CategoricalIndex.astype(dtype, copy=True)

Series.str.endswith(pat, na=nan)

DatetimeIndex.tz_convert(tz)

Panel.tz_convert(tz, axis=0, level=None, copy=True)

Index.value_counts(normalize=False, sort=True, ascending=False, bins=None, dropna=True)

Series.size return the number of elements in the underlying data