统计一段时期内股票的涨幅情况

# -*- coding: utf-8 -*-
\'\'\'加载模块\'\'\'
import sqlalchemy
import pandas
\'\'\'连接数据库\'\'\'
engine = sqlalchemy.create_engine(\'mssql+pyodbc://sa:123456@XiTongDSN\')
connection = engine.connect()
\'\'\'股票代码列表\'\'\'
codelist = pandas.read_sql(\'codelist\', engine)
\'\'\'给每个股票算涨幅\'\'\'
rise = []
for i in range(0, len(codelist) - 1):
    data = pandas.read_sql(codelist[\'code\'][i], engine)
    \'\'\'这个 a b 的 0 赋值不能省，由于有些股票会停牌，期间无数据会调用上个股票的 a 值，报错\'\'\'
    a = 0
    b = 0
    for j in range(0, len(data) - 1):
        \'\'\'由于数据库内的数据日期是由大到小排的，懒的调了，就这样也行\'\'\'
        if data[\'date\'][j] == \'2016-03-31\':
            a = data[\'close\'][j]
        if data[\'date\'][j] == \'2016-03-01\':
            b = data[\'close\'][j]
            if not (a == 0 or b == 0):
                c = (a - b) / b
                break
            else:
                c = 0
                break
    rise.append((codelist[\'code\'][i], c, \'2016-03-31\', \'2016-03-01\'))
\'\'\' list 转 dataframe \'\'\'
rise = pandas.DataFrame(rise)
\'\'\'修改列名\'\'\'
rise.columns = [\'code\', \'rise\', \'date_to\', \'date_from\']
\'\'\'按涨幅排序\'\'\'
rise = rise.sort_values(by = \'rise\', ascending = False)
\'\'\'写库\'\'\'
rise.to_sql(\'rise\', engine, if_exists = \'replace\', index = False)
print(\'ok\')

跟通达信股软的涨跌幅排名（相同条件，如不复权，日期一致等）比较了一下，有些出入，我换了普通计算器手工算了一下，还是跟通达信的有出入，真是不知道通达信的公式是什么