Excel 公式查找索引的匹配部分

Question

I'm working with structure like tree graph. I have items where each one has index telling where it appears in the tree. Then i get groups of items like this:
Item 1: A-1-1-2-1-1-1
Item 2: A-1-1-1-1-2
Item 3: A-1-1-2-1-1-2
Item 4: A-1-1-2-1

What i need to find is common part of index for each group.In this example a common part would be "A-1-1-".
Is it possible to find matching part of the string in another string using excel formulas? My collague said i'd need to make vba macro using recursion to find only part of matching string, but maybe there's simplier solution we didn't find.

Answer 1

Use:

=LEFT(A1,MAX(IF(COUNTIF(A1:A4,LEFT(A1,ROW($ZZ$1:INDEX($ZZ:$ZZ,LEN(A1))))&"*")=COUNTA(A1:A4),ROW($ZZ$1:INDEX($ZZ:$ZZ,LEN(A1))))))

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