* 定义函数：从字符串左边截取到指定字符（不包括该字符） capture program drop ustrleft_until_char program define ustrleft_until_charsyntax varlist(numeric min=1 max=1) [if] [in], char(string)marksample tousetempvar resultgen `result' = ""foreach v of varlist `varlist' {replace `result' = ustrleft(`v', strpos(`v', "`char'") - 1) if `touse' }replace `result' = "" if strpos(`varlist', "`char'") == 0 & `touse' return local result `result' end* 定义函数：从字符串左边截取到指定字符（不包括该字符） capture program drop ustrleft_until_char program define ustrleft_until_charsyntax varlist(numeric min=1 max=1) [if] [in], char(string)marksample tousetempvar resultgen `result' = ""foreach v of varlist `varlist' {replace `result' = ustrleft(`v', strpos(`v', "`char'") - 1) if `touse' }replace `result' = "" if strpos(`varlist', "`char'") == 0 & `touse' return local result `result' end* 示例数据 clear input str20 myvar "北京市海淀区" "上海市浦东新区" "广州市天河区" "深圳市南山区" end* 调用函数：截取到"市"字前部分 ustrleft_until_char myvar, char("市")* 查看结果 list