duplicates

I have a weird result for my data.table v1.9.2 : DT timestamp 1: 2013-01-01 17:51:00.707 2: 2013-01-01 17:51:59.996 3: 2013-01-01 17:52:00.059 4: 2013-01-01 17:54:23.901 5: 2013-01-01 17:54:23.914 str(DT) Classes ‘data.table’ and 'data.frame': 5 obs. of 1 variable: $ timestamp: POSIXct, format: "2013-01-01 17:51:00.707" "2013-01-01 17:51:59.996" "2013-01-01 17:52:00.059" "2013-01-01 17:54:23.901" ... - attr(*, "sorted")= chr "timestamp" - attr(*, ".internal.selfref")=<externalptr> When I apply the duplicated() function I get the following result: duplicated(DT) [1] FALSE FALSE FALSE FALSE TRUE

I have a data frame df with rows that are duplicates for the names column but not for the values column: name value etc1 etc2 A 9 1 X A 10 1 X A 11 1 X B 2 1 Y C 40 1 Y C 50 1 Y I need to aggregate the duplicate names into one row, while calculating the mean over the values column. The expected output is as follows: name value etc1 etc2 A 10 1 X B 2 1 Y C 45 1 Y I have tried to use df[duplicated(df$name),] but of course this does not give me the mean over the duplicates. I would like to use aggregate() , but the problem is that the FUN part of this function will apply to all the other columns

I wonder if there is a way to unduplicate records WITHOUT sorting?Sometimes, I want to keep original order and just want to remove duplicated records. Is it possible? BTW, below are what I know regarding unduplicating records, which does sorting in the end.. 1. proc sql; create table yourdata_nodupe as select distinct * From abc; quit; 2. proc sort data=YOURDATA nodupkey; by var1 var2 var3 var4 var5; run; You could use a hash object to keep track of which values have been seen as you pass through the data set. Only output when you encounter a key that hasn't been observed yet. This outputs in

My SQL query against a particular view returns me 3 different rows. select * from vwSummary where vidate >= '10-15-2010' and vidate <= '10-15-2010' and idno = '0330' order by viDate But if i run the same query through my entity framework, I get 3 rows but all the 3 rows are same, equivalent to the third row. firstVisibleDate = new DateTime(2010, 10, 15); lastVisibleDate = new DateTime(2010, 10, 15); var p1 = (from v in db.vwSummary where v.viDate >= firstVisibleDate && v.viDate <= lastVisibleDate && v.IDNo == "0330" select v).ToList(); Can someone please help me to resolve this issue. EDIT: I

I'm looking for a code duplication tool that is language agnostic. It's easy to find language specific code duplication tools (for Java, C, PHP, ...), but I'd like to run some code duplication analysis on a templates in a custom syntax. I don't care about advanced parsing of the syntax, just straight line based raw string comparison is fine. Whitespace insensitive matching would be a plus, but not required. (It's not that hard to normalize/eliminate whitespace myself.) Does anybody know a tool that can be (mis)used for something like this? Thanks. Doon Have a look Simian , you can use it for

I'd like to detect duplicate files in a directory tree. When two identical files are found only one of the duplicates will be preserved and the remaining duplicates will be deleted to save the disk space. The duplicate means files having the same content which may differ in file names and path. I was thinking about using hash algorithms for this purpose but there is a chance that different files have the same hashes, so I need some additional mechanism to tell me that the files aren't the same even though the hashes are the same because I don't want to delete two different files. Which

As part of a Java based web app, I'm going to be accepting uploaded .xls & .csv (and possibly other types of) files. Each file will be uniquely renamed with a combination of parameters and a timestamp. I'd like to be able to identify any duplicate files. By duplicate I mean, the exact same file regardless of the name. Ideally, I'd like to be able to detect the duplicates as quickly as possible after the upload, so that the server could include this info in the response. (If the processing time by file size doesn't cause too much of a lag.) I've read about running MD5 on the files and storing