DataFrameの内容を破壊的に変更する方法
DataFrameの内容を破壊的に変更するにはinplaceパラメータでTrue(dropnaやwhereなど)を指定します。
test.csvのデータ
id,name,count,rating 1,abc,13,4.38 2,defgh,4,8.56 3,ij,0,1.25 4,klmnopq,23,3.49 5,rst,11,0.51
import pandas as pd df = pd.read_csv("test.csv") print(df) # id name count rating # 0 1 abc 13 4.38 # 1 2 defgh 4 8.56 # 2 3 ij 0 1.25 # 3 4 klmnopq 23 3.49 # 4 5 rst 11 0.51 df.loc[0, "name"] = pd.NaT df.loc[1, "count"] = pd.NaT df.loc[4, "count"] = pd.NaT print(df) # id name count rating # 0 1 NaT 13 4.38 # 1 2 defgh NaT 8.56 # 2 3 ij 0 1.25 # 3 4 klmnopq 23 3.49 # 4 5 rst NaT 0.51 print(df.dropna()) # id name count rating # 2 3 ij 0 1.25 # 3 4 klmnopq 23 3.49 print(df) # id name count rating # 0 1 NaT 13 4.38 # 1 2 defgh NaT 8.56 # 2 3 ij 0 1.25 # 3 4 klmnopq 23 3.49 # 4 5 rst NaT 0.51 print(df.dropna(inplace=True)) # None print(df) # id name count rating # 2 3 ij 0 1.25 # 3 4 klmnopq 23 3.49