pandas.unique

pandas.unique(values)
基于哈希表的唯一性，唯一值按出现顺序返回。

Parameters

Example

import pandas as pd
df = pd.DataFrame({'site':['google', 'baidu', 'wiki', 'pandas'],
                    'age':[18, 39, 22, 45],
                    'price': [1.0, 2.0, 3.0, 4.0],
                    'color': ['red', 'black', None, 'red']}, index=['first', 'second', 'third', 'forth'])
pd.unique(df.loc[:, 'color'])
---------------------------------------------------
array(['red', 'black', None], dtype=object)

Example

import pandas as pd
df = pd.DataFrame({'site':['google', 'baidu', 'wiki', 'pandas'],
                    'age':[18, 39, 22, 45],
                    'price': [1.0, 2.0, 3.0, 4.0],
                    'color': ['red', 'black', None, 'red']}, index=['first', 'first', 'second', 'second'])
pd.unique(df.index)
--------------------------------------------
array(['first', 'second'], dtype=object)