Replace values with nan in python

Question

I have to set the values of the first 3 rows of dataset in column "alcohol" as NaN

newdf=pd.DataFrame({'alcohol':[np.nan]},index=[0,1,2])
wine.update(newdf)
wine

After running the code, no error is coming and dataframe is also not updated

Srce Cde · Accepted Answer · 2018-11-20 06:35:22Z

1

Assuming alcohol as column.

df.loc[:2, "alcohol"] = np.nan

#alternative
df.alcohol.iloc[:3] = np.nan

answered Nov 20, 2018 at 6:13

Srce Cde

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Comments

jezrael · Accepted Answer · 2018-11-20 07:14:19Z

0

Use iloc with get_loc for position for column alcohol:

wine.iloc[:3, wine.columns.get_loc('alcohol')] = np.nan

Or use loc with first values of index:

wine.loc[wine.index[:3], 'alcohol'] = np.nan

answered Nov 20, 2018 at 6:23

jezrael

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