Groupby Date

from datetime import datetime
import pandas as pd

data = {
    'date' : [
        '2019-05-01 19:47:05.069722', 
        '2019-05-02 17:47:05.069722', 
        '2019-05-02 19:47:05.069722',
        '2019-05-03 18:47:05.069722',
        '2019-05-03 19:47:05.069722',
    ],
    'spent' : [
        13, 
        13,
        11,
        15,
        10
    ]  
}

data

df = pd.DataFrame(data)

df

# Convert to String date teo datetime and then to date
df['date'] = pd.to_datetime(df['date']).dt.date

df

df.groupby('date').mean()

# If you want to get only integers, use as type (or .round(0) since 0.17.0)
df.groupby('date').mean().astype(int)