Python數(shù)據(jù)分析基礎(chǔ)與應(yīng)用電子活頁4-8使用reindex()函數(shù)重置索引排列順序

Python數(shù)據(jù)分析基礎(chǔ)與應(yīng)用模塊電子活頁4-8使用reindex()函數(shù)重置索引排列順序【技能訓(xùn)練4-12】使用reindex()函數(shù)重置索引排列順序【訓(xùn)練要求】在JupyterNotebook開發(fā)環(huán)境中創(chuàng)建j4-12.ipynb，然后編寫代碼使用reindex()函數(shù)重置索引排列順序?！緦嵤┻^程】（1）對Series使用reindex()函數(shù)重置索引排列順序代碼如下：importpandasaspds1=pd.Series([21,22,20,19],index=['d','b','a','c'])print(s1.reindex(['a','b','c','d','e']))輸出結(jié)果：a20.0b22.0c19.0d21.0eNaNdtype:float64代碼如下：#使用fill_value()參數(shù)指定不存在元素的默認(rèn)值為0print(s1.reindex(['a','b','c','d','e'],fill_value=0))輸出結(jié)果：a20b22c19d21e0dtype:int64代碼如下：s2=pd.Series(['blue','red','yellow'],index=[0,2,4])#使用ffill函數(shù)前向填充s2.reindex(range(6),method='ffill')輸出結(jié)果：0blue1blue2red3red4yellow5yellowdtype:object（2）對DataFrame使用reindex()函數(shù)重置行索引或列索引的排列順序代碼如下：importpandasaspddata1={'date':pd.Series(['2022/1/1','2022/1/2','2022/1/3','2022/1/4','2022/1/5']),'highT':pd.Series([12,15,12,12,7]),'lowT':pd.Series([1,4,8,6,5]),'AQI':pd.Series([167,145,123,212,104])}df1=pd.DataFrame(data1)#重置行、列索引的排列順序df2=df1.reindex(index=[4,0,2],columns=['date','AQI','highT','lowT'])print(df2)輸出結(jié)果：dateAQIhighTlowT42022/1/51047502022/1/116712122022/1/3123128代碼如下：#為DataFrame添加一個新的行df3=df1.reindex(index=[4,0,2,5])print(df3)輸出結(jié)果：datehighTlowTAQI42022/1/57.05.0104.002022/1/112.01.0167.022022/1/312.08.0123.05NaNNaNNaNNaN代碼如下：#使用ffill函數(shù)前向填充df3=df1.reindex(index=[4,0,2,5],method='ffill')print(df3)輸出結(jié)果：datehighTlowTAQI42022/1/57510402022/1/112116722022/1/312812352022/1/575104代碼如下：#為DataFrame添加一個新的列df4=df1.reindex(columns=['date','AQI','highT','lowT','grade'])print(df4)輸出結(jié)果：dateAQIhighTlowTgrade02022/1/1167121NaN12022/1/2145154NaN22022/1/3123128NaN32022/1/4212126NaN42022/1/510475NaN代碼如下：#使用fill-value參數(shù)指定不存在元素的默認(rèn)值為0df4=df1.reindex(columns=['date','AQI','highT','lowT','grade'],fill_value=0)print(df4)輸出結(jié)果：dateAQIhighTlowTgrade02022/1/1167121012022/1/214515