gistfile1.txt

categorical = ['PULocationID', 'DOLocationID']

def read_data(filename):
    df = pd.read_parquet(filename)
    
    df['duration'] = df.tpep_dropoff_datetime - df.tpep_pickup_datetime
    df['duration'] = df.duration.dt.total_seconds() / 60

    df = df[(df.duration >= 1) & (df.duration <= 60)].copy()

    df[categorical] = df[categorical].fillna(-1).astype('int').astype('str')
    
    return df