fileexists:告诉你“我”存在吗？

clear allcap mkdir d:/fileexistscd d:/fileexistsset obs 1gen v1=fileexists("temp.txt")gen v2=fileexists("title_1.dta")list v1 v2

clear allcap mkdir d:/fileexistscd d:/fileexistsforvalues j=1/37{  cap copy "https://www.boc.cn/custserv/bi2/index_`j'.html" temp`j'.txt,replace  while fileexists("temp`j'.txt") == 0 {    sleep 5000    cap copy "https://www.boc.cn/custserv/bi2/index_`j'.html" temp`j'.txt,replace  }    infix strL v 1-10000 using "temp`j'.txt",clear //观察后不用进行转码，可直接进行下一步    forvalues i=`=_N'(-1)2{        if index(v[`i'],"</li>") & !index(v[`i'],"</a>") {         replace v=v+v[`i'] in `=`i'-1'         drop in `i'        }  } //按某种标志进行合并    keep if index(v,"</span></li>")    gen url=ustrregexs(1) if ustrregexm(v,`"<a href="(.*?)""')    forvalues k=1/`=_N' {        if ustrregexm(url[`k'],"^../../"){            replace url= "https://www.boc.cn"+substr(url,6,.) in `k'         }        if ustrregexm(url[`k'],"^./"){            replace url=  "https://www.boc.cn/custserv/bi2/"+substr(url,3,.) in `k'       }  } //两种不同的链接，分类进行处理。    gen title=ustrregexs(1) if ustrregexm(v,`"title="(.*?)""')    gen date=ustrregexs(1) if ustrregexm(v,"<span>(.*?)</span>")    replace date=substr(date,3,11)    drop v    save title_`j',replace}
clear forvalues i=1/37{  append using title_`i'}sort datesave title_total,replace