duplicates

OK, there are a lot of examples of duplicate detection and removal in php arrays, using array_unique() etc but what if you want to find dups, modify them, check again in a loop until all dups are now unique? I think it's something like using array_filter()... so as a more specific example, here's what would come out of a sql statement something like this: SELECT id, list.comboname FROM list INNER JOIN ( SELECT comboname FROM list GROUP BY comboname HAVING count(id) > 1 ) dup ON list.comboname = dup.comboname To an array of the duplicates in the table: Array ( [0] => 49 [1] => big.dup [2] =>

I have almost 3.000 CSV files (containing tweets) with the same format, I want to merge these files into one new file and remove the duplicate tweets. I have come across various topics discussing similar questions however the number of files is usually quit small. I hope you can help me write a code within R that does this job both efficiently and effectively. The CSV files have the following format: Image of CSV format: I changed (in column 2 and 3) the usernames (on Twitter) to A-E and the 'actual names' to A1-E1. Raw text file: "tweet";"author";"local.time" "1";"2012-06-05 00:01:45 @A (A1):

Is there an optimal solution to this problem? Describe an algorithm for finding duplicates in a file of one million phone numbers. The algorithm, when running, would only have two megabytes of memory available to it, which means you cannot load all the phone numbers into memory at once. My 'naive' solution would be an O(n^2) solution which iterates over the values and just loads the file in chunks instead of all at once. For i = 0 to 999,999 string currentVal = get the item at index i for j = i+1 to 999,999 if (j - i mod fileChunkSize == 0) load file chunk into array if data[j] == currentVal

I'm attempting to build a query that will return all non duplicate (unique) records in a table. The query will need to use multiple fields to determine if the records are duplicate. For example, if a table has the following fields; PKID, ClientID, Name, AcctNo, OrderDate, Charge, I'd like to use the AcctNo, OrderDate and Charge fields to find unique records. Table PKID-----ClientID-----Name-----AcctNo-----OrderDate-----Charge 1 JX100 John 12345 9/9/2010 $100.00 2 JX220 Mark 55567 9/9/2010 $23.00 3 JX690 Matt 89899 9/9/2010 $218.00 4 JX100 John 12345 9/9/2010 $100.00 The result of the query

So i'm making a macro to do a bunch of things. one thing is find duplicates of cells in sheet1 from sheet2. given columnA in sheet 1, do any values in columnB on sheet2 match any of the values in columna sheet1. I know theres a remove duplicates, but I just want to mark them, not remove. I was thinking something with the filtering. I know when you filter you can select multiple criteria, so if u have a column with 20 different values in it, you can select 5 values in the filter and it will show rows with those 5 values for the particular column. So i recorded a macro of that, and checked out

I have quite a large table with 19 000 000 records, and I have problem with duplicate rows. There's a lot of similar questions even here in SO, but none of them seems to give me a satisfactory answer. Some points to consider: Row uniqueness is determined by two columns, location_id and datetime . I'd like to keep the execution time as fast as possible (< 1 hour). Copying tables is not very feasible as the table is several gigabytes in size. No need to worry about relations. As said, every location_id can have only one distinct datetime , and I would like to remove all the duplicate instances.