我在表格中有一个字段，用于存储以逗号分隔的多个标记，例如
tag1, tag2, tag3,tag4
对于波斯语版本，我需要用،替换单个逗号
所以标签看起来像
tag1، tag2، tag3،tag4،
我在数据库中有超过三千条记录，标签与،或,一起存储，但我希望所有这些记录都与،分开。
如何使用SQL查找并用,替换所有،。
我使用SQL Server作为我的数据库。
我们说表结构是
表BLOG
博客表格字段
ID int
Title nVarchar(300)
Description nVarchar(500)
Details nVarchar(max)
Date DateTime
Tags nVarchar(300)
Image varchar(60)
CategoryID int
Updated DateTime
Created DateTime
Published Boolean
答案 0 :(得分：1)
您是否尝试过使用import numpy as np
import pandas as pd
import datetime as dt
import matplotlib.pyplot as plt
import calendar
# frame
from get_year_deltas import get_year_deltas
from constant_short_rate import constant_short_rate
from market_environment import market_environment
from plot_option_stats import plot_option_stats
# simulation
from sn_random_numbers import sn_random_numbers
from simulation_class import simulation_class
from geometric_brownian_motion import geometric_brownian_motion
from jump_diffusion import jump_diffusion
from square_root_diffusion import square_root_diffusion
# valuation
from valuation_class import valuation_class
from valuation_mcs_european import valuation_mcs_european
from valuation_mcs_american import valuation_mcs_american
from derivatives_position import derivatives_position
from derivatives_portfolio import derivatives_portfolio
#import os
#path = os.getcwd()
url = 'http://www.stoxx.com/download/historical_values/h_vstoxx.txt'
vstoxx_index = pd.read_csv(url, index_col=0, header=2,parse_dates=True, dayfirst=True)
vstoxx_index = vstoxx_index[('2013/12/31' < vstoxx_index.index) & (vstoxx_index.index < '2014/4/1')]
vstoxx_futures = pd.read_excel('./vstoxx_march_2014.xlsx', 'vstoxx_futures')
del vstoxx_futures['A_SETTLEMENT_PRICE_SCALED']
del vstoxx_futures['A_CALL_PUT_FLAG']
del vstoxx_futures['A_EXERCISE_PRICE']
del vstoxx_futures['A_PRODUCT_ID']
columns = ['DATE', 'EXP_YEAR', 'EXP_MONTH', 'PRICE']
vstoxx_futures.columns = columns
def third_friday(date):
day = 21 - (calendar.weekday(date.year, date.month, 1) + 2) % 7
return dt.datetime(date.year, date.month, day)
set(vstoxx_futures['EXP_MONTH'])
third_fridays = {}
for month in set(vstoxx_futures['EXP_MONTH']):
third_fridays[month] = third_friday(dt.datetime(2014, month, 1))
#third_fridays
tf = lambda x: third_fridays[x]
vstoxx_futures['MATURITY'] = vstoxx_futures['EXP_MONTH'].apply(tf)
#vstoxx_futures.tail()
vstoxx_options = pd.read_excel('./vstoxx_march_2014.xlsx', 'vstoxx_options')
#vstoxx_options.info()
del vstoxx_options['A_SETTLEMENT_PRICE_SCALED']
del vstoxx_options['A_PRODUCT_ID']
columns = ['DATE', 'EXP_YEAR', 'EXP_MONTH', 'TYPE', 'STRIKE', 'PRICE']
vstoxx_options.columns = columns
vstoxx_options['MATURITY'] = vstoxx_options['EXP_MONTH'].apply(tf)
#vstoxx_options.head()
vstoxx_options['STRIKE'] = vstoxx_options['STRIKE'] / 100.0
save = False
if save is True:
import warnings
warnings.simplefilter('ignore')
h5 = pd.HDFStore('./vstoxx_march_2014.h5', complevel=9, complib='blosc')
h5['vstoxx_index'] = vstoxx_index
h5['vstoxx_futures'] = vstoxx_futures
h5['vstoxx_options'] = vstoxx_options
h5.close()
pricing_date = dt.datetime(2014, 3, 31)
# last trading day in March 2014
maturity = third_fridays[10]
# October maturity
initial_value = vstoxx_index['V2TX'][pricing_date]
# VSTOXX on pricing_date
forward = vstoxx_futures[(vstoxx_futures.DATE == pricing_date) & (vstoxx_futures.MATURITY == maturity)]['PRICE'].values[0]
tol = 0.20
option_selection = vstoxx_options[(vstoxx_options.DATE == pricing_date)
& (vstoxx_options.MATURITY == maturity)
& (vstoxx_options.TYPE == 'C')
& (vstoxx_options.STRIKE > (1 - tol) * forward)
& (vstoxx_options.STRIKE < (1 + tol) * forward)]
me_vstoxx = market_environment('me_vstoxx', pricing_date)
me_vstoxx.add_constant('initial_value', initial_value)
me_vstoxx.add_constant('final_date', maturity)
me_vstoxx.add_constant('currency', 'EUR')
me_vstoxx.add_constant('frequency', 'B')
me_vstoxx.add_constant('paths', 10000)
csr = constant_short_rate('csr', 0.01)
# somewhat arbitrarily chosen here
me_vstoxx.add_curve('discount_curve', csr)
# parameters to be calibrated later
me_vstoxx.add_constant('kappa', 1.0)
me_vstoxx.add_constant('theta', 1.2 * initial_value)
vol_est = vstoxx_index['V2TX'].std() * np.sqrt(len(vstoxx_index['V2TX']) / 252.0)
me_vstoxx.add_constant('volatility', vol_est)
# vol_est
vstoxx_model = square_root_diffusion('vstoxx_model', me_vstoxx)
me_vstoxx.add_constant('strike', forward)
me_vstoxx.add_constant('maturity', maturity)
payoff_func = 'np.maximum(maturity_value - strike, 0)'
vstoxx_eur_call = valuation_mcs_european('vstoxx_eur_call',vstoxx_model, me_vstoxx, payoff_func)
option_models = {}
for option in option_selection.index:
strike = option_selection['STRIKE'].ix[option]
me_vstoxx.add_constant('strike', strike)
option_models[option] = valuation_mcs_european( 'eur_call_%d' % strike, vstoxx_model, me_vstoxx, payoff_func )
def calculate_model_values(p0):
'''
Returns all relevant option values.
Parameters
p0 : tuple/list, tuple of kappa, theta, volatility
Returns
model_values : dict, dictionary with model values
'''
kappa, theta, volatility = p0
vstoxx_model.update(kappa=kappa,
theta=theta,
volatility=volatility)
model_values = {}
for option in option_models:
model_values[option] = option_models[option].present_value(fixed_seed=True)
return model_values
# calculate_model_values((0.5, 27.5, vol_est))
i = 0
def mean_squared_error(p0):
'''
Returns the mean-squared error given the model and market values.
Parameters
p0 : tuple/list, tuple of kappa, theta, volatility
Returns
MSE : float, mean-squared error
'''
global i
model_values = np.array(calculate_model_values(p0).values())
market_values = option_selection['PRICE'].values
option_diffs = model_values - market_values
MSE = np.sum(option_diffs ** 2) / len(option_diffs)
# vectorized MSE calculation
if i % 20 == 0:
if i == 0:
print( '%4s' % i, '%6s' % "kappa", '%6s' % "theta", '%6s —>' % "vola", '%6s' % "MSE")
print( '%4d' % i, '%6.3f' % p0[0], '%6.3f' % p0[1], '%6.3f —>' % p0[2], '%6.3f' % MSE )
i += 1
return MSE
mean_squared_error((0.5, 27.5, vol_est))
：
REPLACE()查找并替换为Unicode字符