Using a numpy array of length less than pandas dataframe to fill in pandas dataframe

Question

df = pd.DataFrame(index=pd.date_range('2017-01-01', '2017-01-10', freq='D'), columns=['test'])

vals = np.array([1.0, 2.0])

df['test'] = vals

I get this error: ValueError: Length of values does not match length of index

Any way I can fix it? This error is arising because lenght of vals is less than length of df. I want to insert numpy NaNs for the places where I have no values.

John Zwinck · Accepted Answer · 2017-04-02 03:51:55Z

3

You can assign to just the first rows like this:

df['test'][:len(vals)] = vals

answered Apr 2, 2017 at 3:51

John Zwinck

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1 Comment

user308827 Over a year ago

sweet! so obvious now that you have posted the soln

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