简单说明dtype使用方法：

Rule为规则类，其中有3个字段，1为类型，2为计算规则，3为保留位数

如 :'close': Rule(float64, 1 / 10000.0, 2),

表示收盘价，Rule有三个字段，首为浮点类型，次为计算规则，末为保留小数位数

Converter类则是Rule字典集合，这里表示的为open,close等为key的集合

# /usr/bin/python3

# -*- encoding: utf-8 -*-

from collections import namedtuple

import numpy as np


float64 = np.dtype('float64')

Rule = namedtuple('Rule', ['dtype', 'multiplier', 'round'])

class Converter(object):

    def __init__(self, rules):

        self._rules = rules


    def convert(self, name, data):

        try:

            r = self._rules[name]

        except KeyError:

            return data


        result = data * r.multiplier

        if r.round:

            result = np.round(result, r.round)


        return result


    def field_type(self, name):

        try:

            return self._rules[name].dtype

        except KeyError:

            return self._rules['open'].dtype


if __name__ == '__main__':


    StockBarConverter = Converter({

        'open': Rule(float64, 1 / 10000.0, 4),

        'close': Rule(float64, 1 / 10000.0, 2),

        'high': Rule(float64, 1 / 10000.0, 2),

        'low': Rule(float64, 1 / 10000.0, 2),

        'limit_up': Rule(float64, 1/10000.0, 2),

        'limit_down': Rule(float64, 1/10000.0, 2),

        'volume': Rule(float64, 1, 0),

    })

    _converter = StockBarConverter

    data = np.array([1001, 2103])

    result = _converter.convert('open', data)

    open_type = _converter.field_type("open")

    print("open_type: ", open_type) #open_type:  float64