/ * showcase the use of string function substr(s, n1, n2)
di substr("KLSDFJKDFH", 1, 2)


Obviously, you may read carefully on the help document on the function:
help substr

gen newvar=substr(oldvar,1,2)。参见https://bbs.pinggu.org/thread-1424061-1-1.html。但这一命令只能实现你知道截取部分的具体位置时才能使用，当其位置不确定时就不好办了。

https://bbs.pinggu.org/thread-1168044-1-1.html

谢谢，非常有帮助~

字符串截取挺好