Drop rows of selected rows with null values

Question

I want to drop rows with null values in both column a and b. I have managed to find those rows with:

df[(df['a'].isnull()) & (df['b'].isnull())]

How do I drop these rows?

You just invert the mask: `df[~((df['a'].isnull()) & (df['b'].isnull()))]` I'm sure this has been answered before, looking for dupe — EdChum, Nov 14 '17 at 08:42
df.dropna(subset=['a','b'], how='all') really does what I want. And I think its a better approach. Thanks ! — Chia Yi, Nov 14 '17 at 08:58

score 0 · Accepted Answer · answered Nov 14 '17 at 08:42

0

Invert mask by ~:

df[~(df['a'].isnull() & df['b'].isnull())]

Or:

df[df[['a','b']].notnull().any(1)]

answered Nov 14 '17 at 08:42

jezrael

1

Thanks @jezrael ! df.dropna(subset=['a','b'], how='all') does what I want too ! – Chia Yi Nov 14 '17 at 08:59

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