以30个交易日为一轮并处理相关交易，比如说要把万科的5月9号和10号的数据加起来变成新的一期，请问如何实现


* Example generated by -dataex-. To install: ssc install dataex
clear
input str12 name str10 time float price_ long delta_share
"平安银行" "2009-11-03" 1737    -700
"平安银行" "2011-05-06"  984  -13000
"平安银行" "2014-08-12"   64  -60000
"平安银行" "2014-11-28"  330   -7680
"平安银行" "2017-06-27" 5662   -2100
"平安银行" "2017-11-20"  463   -2000
"万科A"      "2007-05-09" 1403  -20000
"万科A"      "2007-05-10" 1443  -20000
"万科A"      "2007-07-23" 1911  -46900
"万科A"      "2009-08-12"  374 -140000
"万科A"      "2010-03-24" 5681   -1000
"万科A"      "2010-11-04" 5722  -38000
"万科A"      "2014-12-01"   93 -123059
"万科A"      "2014-12-02"   92  -50000
"万科A"      "2014-12-04"  226  -14606
end
label values price_ price_
label def price_ 64 "10.59", modify
label def price_ 92 "10.87", modify
label def price_ 93 "10.88", modify
label def price_ 226 "11.65", modify
label def price_ 330 "12.25", modify
label def price_ 374 "12.69", modify
label def price_ 463 "13.29", modify
label def price_ 984 "17.74", modify
label def price_ 1403 "21.50", modify
label def price_ 1443 "21.90", modify
label def price_ 1737 "24.81", modify
label def price_ 1911 "26.54", modify
label def price_ 5662 "9.29", modify
label def price_ 5681 "9.48", modify
label def price_ 5722 "9.89", modify
[/CODE]