Example of using np.dtype to structure data

structured_type_example.py

var_space = np.dtype([
    ('name', 'S5'),       # 5 bytes for the name
    ('age', 'i1'),        # 1 byte for the age
    ('weight', 'f4')      # 4 bytes for the weight value
])                        # 10 bytes in total to describe 1 person


def init_persons(n:int) -> np.ndarray: 
    '''Get initial values for n persons.
    Return numpy.ndarray of dtype var_space'''
    persons = np.zeros(n, dtype=var_space)
    for i in range(n):
        persons[i]['name'] = input('Name [5 letters]: ')
        persons[i]['age'] = int(input('Age: '))
        persons[i]['weight'] = float(input('Weight, kg: '))
    return persons


n = 3
persons = init_persons(n)
for i, record in enumerate(persons):
    print('{}. {}, size={}'.format(i, record, record.itemsize))