def main():
    df = pd.DataFrame(data=np.zeros((0, 3)), columns=['word', 'gender',
        'source'])
df['word'] = ('banana', 'banana', 'elephant', 'mouse', 'mouse', 'elephant',
    'banana', 'mouse', 'mouse', 'elephant', 'ostrich', 'ostrich')
df['gender'
    ] = 'a', 'the', 'the', 'a', 'the', 'the', 'a', 'the', 'a', 'a', 'a', 'the'
Merging crosstabs in Python