testing_utils.py 文件源码

def random_dataframe():
    """Generates a DataFrame with five random walk columns and a tag column"""
    arr = np.cumsum(np.random.randn(50, 5), axis=1)
    letters = itertools.combinations(string.ascii_uppercase, 3)
    columns = [''.join(triplet) for triplet in random.choices(list(letters), k=5)]
    tags = [chr(i + 65) for i in np.random.randint(0, 5, 50)]
    ix = pd.date_range(end=pd.Timestamp.utcnow(), periods=50, freq='90min')

    df = pd.DataFrame(arr, columns=columns)
    df['tag'] = tags
    df.index = ix
    return df