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One of our users has two sets of contacts in his email: 7000 or so from and old mail system, and even more in his current Apple Address Book. What we're trying to do is get the two sets of contacts into similar formats (.csv, .xls, whatever) and compare to look for duplicates. I suspect the larger set includes all of the entries from the smaller one, but I'd like to prove that with some kind of checking tool without scrolling through the list manually.

Can anyone recommend any tools to do something like this?

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Gmail has an automatic duplicates detector. You could:

  1. Set up a new account
  2. Import both sets of contacts
  3. Use the Gmail duplicates finder to delete and merge them
  4. Export into a master contact list.

Your user would also get a bonus Gmail account out of it...

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Removing duplicates from your list with Excel:

Paste your complete list into Column A. Sort the entire column alphabetically (A > Z).

Select Column B, enter the following into the "formula" box


Run the formula.

Keeping Column B still selected, go to the menu: Edit > Fill > Down.

Column B will fill up an updated list with no duplicates.

Again select Column B, and choose Edit > Copy. (Simple copy paste won't work) Create a new spreadsheet, and select Edit > Paste Special > "Values" (or "Text" if you are using suppose Libre Office).

Sort your list now, by removing blank lines manually or with data filter.

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up vote 0 down vote accepted

I ended up using an Excel add-in called DigDB. It allowed me to de-duplicate each of my sets individually, then compare/de-dupe, and consolidate the two sets into one. I've now got a unified set we're happy with.

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Not sure about Apple apps but if you can export both to xls and get them to a Windows installation then a program called Beyond Compare will do a comparison of the contents on a row by row basis

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