你若要问程序，永远附上资料；若要附上资料，永远用 dataex 印出资料；先 ssc install dataex (并见说明)，将原始 Stata 资料中具有”代表性”的一部分资料列出，以供有意回答者实验之用，并能提供具体操作指令。并请参考 http://www.jianshu.com/p/9870080fe769,  https://bbs.pinggu.org/thread-5048204-1-1.html, 与 https://bbs.pinggu.org/thread-5917273-1-1.html。

你是字符型的吧？先占转为数值型的变量吧？

替换字符串中的字符
在本例中，可以用如下命令
subinstr(varname," ","",.)

以下是命令参考
1.subinstr(s1,s2,s3,n)
Description:s1, where the first n occurrences in s1 of s2 have been replaced with s3
subinstr() is intended for use with only plain ASCII characters and for use by programmers who want to perform byte-based substitution.  Note that any Unicode character beyond ASCII range (code point greater than 127) takes more than 1 byte in the UTF-8 encoding; for example, é takes 2 bytes.
To perform character-based replacement in Unicode strings, see usubinstr().
If n is missing, all occurrences are replaced.
Also see regexm(), regexr(), and regexs().
subinstr("this is the day","is","X",1) = "thX is the day"
subinstr("this is the hour","is","X",2) = "thX X the hour"
subinstr("this is this","is","X",.) = "thX X thX"
Domain s1:strings (to be substituted into)
Domain s2:strings (to be substituted from)
Domain s3:strings (to be substituted with)
Domain n: integers > 0 or missing
Range:strings

2.subinword(s1,s2,s3,n)
Description:  s1, where the first n occurrences in s1 of s2 as a word have been replaced with s3
A word is defined as a space-separated token.  A token at the beginning or end of s1 is considered space-separated.  This is different from Unicode word, which is a language unit based on either a set of word-boundary rules or dictionaries for several languages (Chinese, Japanese, and Thai).  If n is missing, all occurrences are replaced.
Also see regexm(), regexr(), and regexs().
subinword("this is the day","is","X",1) = "this X the day"
subinword("this is the hour","is","X",.) = "this X the hour"
subinword("this is this","th","X",.) = "this is this"
Domain s1:strings (to be substituted for)
Domain s2:strings (to be substituted from)
Domain s3:strings (to be substituted with)
Domain n: integers > 0 or missing
Range:strings
Remarks
Use function usubinstr() if your string contains Unicode characters.

已找到命令
misstable summarize // 所有变量
misstable sum var // 指定变量
drop if missing(var1,var2,var3,var4) //如果四个变量中有一个有缺漏值，即那条观察值就被删除

replace v=subinstr(v," ","",.)