Checking for the Existence of a File

John has a column of invoice numbers in a worksheet. He has a directory on the network where staff save a PDF of the actual invoice and name it using the same invoice number that is in the worksheet. Each invoice number in the worksheet should have a correspondingly named PDF in the directory on the network. John is looking for a way, within Excel, to check and verify that a PDF really does exist for each invoice number.

There is no way to do this using built-in Excel commands. You can, however, create a macro that will do the checking for you. For instance, consider the following simple user-defined function:

Function FileExists1(sPath As String)
    FileExists = Dir(sPath) <> ""
End Function

The routine simply returns a True or False value, based on whether the specified file exists. The value that is passed to the function needs to include a full path and file name. For example, if the file specification (including the path) were in cell A1, you could use the following in a cell:

=FileExists1(A1)

You may not, however, want to put the full path name into the cell. In that case, you could specify it in the actual formula, in this way:

=FileExists1("c:\your\path\here\" & A1 & ".pdf")

Of course, you could instead specify the path in the user-defined function:

Function FileExists2(sFile As String)
    sPath = "c:\your\path\here\" & sFile & ".pdf"
    FileExists = Dir(sPath) <> ""
End Function

With such a function you could easily create a formula in your worksheet that would "flag" any invoices missing from the directory:

=IF(FileExists2(A1),"","Missing Invoice")

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (7512) applies to Microsoft Excel 97, 2000, 2002, and 2003. You can find a version of this tip for the ribbon interface of Excel (Excel 2007 and later) here: Checking for the Existence of a File.