求助用公式提取出现过2次的4字符数据

TEXTJOIN(",",1,UNIQUE(FILTER(A1:A9,(LEN(A1:A9)=4)*(COUNTIF(A1:A9,A1:A9)=2))))

【《Excel你问我答挑战》一列数据里,筛选出,字符串长度为4,出现次数为2的数据,还要去重输出,要求真多,小麻烦】 https://www.bilibili.com/video/BV1W24y157rM

=IFERROR(INDEX(A$1:A$11,SMALL(IF((MATCH(A$1:A$11,A$1:A$11,)=ROW($1:$11))*(LEN(A$1:A$11)=4)*(COUNTIF(A$1:A$11,A$1:A$11)=2),ROW($1:$11)),ROW(A1))),"")
或
=UNIQUE(FILTER(A1:A11,(LEN(A1:A11)=4)*(COUNTIF(A1:A11,A1:A11)=2)))