1. 答案:
help string functions
gen n_negative1 = (strlen(recode) - strlen(subinstr(recode, negative1, "", .)))/strlen(negative1)
2. 建议:
2.1 用Stata处理双字节的中文并不理想
help limits // see: length of a string variable
2.2 中文文本处理存在分词方面的固有困难,看
http://baike.baidu.com/view/19109.htm?func=retitle#5