原文: Excel公式 提取文件路径后缀
我们在代码中获取一个文件路径的后缀，是一个很简单的事.
如C#中，可以通过new FileInfo(filePath).Extension，或者Path.GetExtension(filePath)获取。
而Excel的大数据中，直接批量获取同行单元格内容中文件路径的后缀，该如何获取？
如上，想获取文件后缀，然后从中分析出文件的所属开发语言。
公式如下：
1、获取后缀
=RIGHT(D2,LEN(D2)-FIND("@",SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",)))))
过程分析：
我们需要先找到最后的一个字符"."的位置,这样才能通过Right函数截取相应的长度，获取后缀。
而找字符，我们用Find函数就行了。但是怎么找到那唯一的一个呢？
我们通过先通过LEN(D2)-LEN(SUBSTITUTE(D2,".",)查找字符串中有多少个同样的字符"." ,然后这个数量也就可以代表最后一个字符的顺序。
最后一个字符找到了，我们可以SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",)))将它替换成一个在这段内容中不会出现的字符@。
然后直接找字符@就行了，FIND("@",SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",))))，找到字符@的位置，再用字符串的总长度减去位置，就能得到字符从右往左的位置。
通过Right函数截取，即可。
2、后缀得到了，再判断是何语言。一个所属开发语言的项目，包含的文件类型都是有规律的。
如C#里面，类文件是cs。数据库sql文件，后缀是sql。
而我们在Excel中只要用if就能判断出来。
=IF(ISBLANK(D2),"",IF(OR(RIGHT(D2,LEN(D2)-FIND("@",SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",)))))="frm",RIGHT(D2,LEN(D2)-FIND("@",SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",)))))="bas",RIGHT(D2,LEN(D2)-FIND("@",SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",)))))="cls"),"VB",IF(RIGHT(D2,LEN(D2)-FIND("@",SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",)))))="cs","C#",IF(OR(RIGHT(D2,LEN(D2)-FIND("@",SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",)))))="c",RIGHT(D2,LEN(D2)-FIND("@",SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",)))))="h"),"C++",IF(RIGHT(D2,LEN(D2)-FIND("@",SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",)))))="sql","SP",IF(RIGHT(D2,LEN(D2)-FIND("@",SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",)))))="4gl","4gl",IF(OR(RIGHT(D2,LEN(D2)-FIND("@",SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",)))))="bat",RIGHT(D2,LEN(D2)-FIND("@",SUBSTITUTE(D2,".","@",LEN(D2)-LEN(SUBSTITUTE(D2,".",)))))="sh"),"BAT","UnKnown")))))))
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注意一下异常情况，如单元格为空，需要加个判断IsBlank或者SUBSTITUTE(D2," ","")=""等
案例Demo：
language公式：
=IF(ISBLANK(E2),"",IF(OR(RIGHT(E2,LEN(E2)-FIND("@",SUBSTITUTE(E2,".","@",LEN(E2)-LEN(SUBSTITUTE(E2,".",)))))="frm",RIGHT(E2,LEN(E2)-FIND("@",SUBSTITUTE(E2,".","@",LEN(E2)-LEN(SUBSTITUTE(E2,".",)))))="bas",RIGHT(E2,LEN(E2)-FIND("@",SUBSTITUTE(E2,".","@",LEN(E2)-LEN(SUBSTITUTE(E2,".",)))))="cls"),"VB",IF(RIGHT(E2,LEN(E2)-FIND("@",SUBSTITUTE(E2,".","@",LEN(E2)-LEN(SUBSTITUTE(E2,".",)))))="cs","C#",IF(OR(RIGHT(E2,LEN(E2)-FIND("@",SUBSTITUTE(E2,".","@",LEN(E2)-LEN(SUBSTITUTE(E2,".",)))))="c",RIGHT(E2,LEN(E2)-FIND("@",SUBSTITUTE(E2,".","@",LEN(E2)-LEN(SUBSTITUTE(E2,".",)))))="h"),"C++",IF(RIGHT(E2,LEN(E2)-FIND("@",SUBSTITUTE(E2,".","@",LEN(E2)-LEN(SUBSTITUTE(E2,".",)))))="sql","SP",IF(RIGHT(E2,LEN(E2)-FIND("@",SUBSTITUTE(E2,".","@",LEN(E2)-LEN(SUBSTITUTE(E2,".",)))))="4gl","4gl",IF(OR(RIGHT(E2,LEN(E2)-FIND("@",SUBSTITUTE(E2,".","@",LEN(E2)-LEN(SUBSTITUTE(E2,".",)))))="bat",RIGHT(E2,LEN(E2)-FIND("@",SUBSTITUTE(E2,".","@",LEN(E2)-LEN(SUBSTITUTE(E2,".",)))))="sh"),"BAT","UnKnown")))))))
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Project公式：
=RIGHT(LEFT(E2,FIND("@",SUBSTITUTE(E2,"\","@",LEN(E2)-LEN(SUBSTITUTE(E2,"\",))))-1),LEN(LEFT(E2,FIND("@",SUBSTITUTE(E2,"\","@",LEN(E2)-LEN(SUBSTITUTE(E2,"\",))))-1))-FIND("@",SUBSTITUTE(LEFT(E2,FIND("@",SUBSTITUTE(E2,"\","@",LEN(E2)-LEN(SUBSTITUTE(E2,"\",))))-1),"\","@",LEN(LEFT(E2,FIND("@",SUBSTITUTE(E2,"\","@",LEN(E2)-LEN(SUBSTITUTE(E2,"\",))))-1))-LEN(SUBSTITUTE(LEFT(E2,FIND("@",SUBSTITUTE(E2,"\","@",LEN(E2)-LEN(SUBSTITUTE(E2,"\",))))-1),"\",)))))
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文件名公式：
=RIGHT(E2,LEN(E2)-FIND("@",SUBSTITUTE(E2,"\","@",LEN(E2)-LEN(SUBSTITUTE(E2,"\",)))))