excel提取主域名

=IF(LEFT(LEFT(SUBSTITUTE(A1,"http://",""),FIND("/",SUBSTITUTE(A1,"http://","")&"/")-1),4)="www.",MID(LEFT(SUBSTITUTE(A1,"http://",""),FIND("/",SUBSTITUTE(A1,"http://","")&"/")-1),5,256),LEFT(SUBSTITUTE(A1,"http://",""),FIND("/",SUBSTITUTE(A1,"http://","")&"/")-1))