How do I search a list of numbers for duplicates and drop the first of 2 duplicated values by 1? : <p>I get a list of numbers 90 - 480; this range is not completely filled. What I mean is that the list may be 90, 91, 92, 94, 95...and so on up to 480 and the missing 93 is expected. Every time I get the list there are lots of duplicates. Also, I might get up to 10 lists at a time. What I do know about the list is that if there are duplicates, 100% of the time, if I drop the first of the 2 duplicates by 1 value, then continue scanning for duplicates this will give me an accurate list. the list might look like: '90, 91, 92, 93, 95, 95, 96, 98, 100, 100, 102, 102.....' so to get this part of the list accurate I will need to change the first 95 to 94, the first 100 to 99, and the first 102 to 101. </p>

<p>Sorry if I am asking in the incorrect place but just for the sake of this question; the list is in excel but I could use Python or Linux as I have access to both of those as well. Thanks!</p>
