unique

问题 I'm working in Visual Studio - VB.NET. My problem is that I want to delete a specific row in SQL Server but the only unique column I have is an Identity that increments automatically. My process of work: 1. I add a row in the column (the identity is being incremented, but I don't know the number) 2. I want to delete the previous row Is there a sort of unique ID that every new record has? It's possible that my table has 2 exactly the same records, just the sequence (identity) is different. Any

问题 I have a jsfiddle. obj = {}; obj[0] = 'hej'; obj[1] = 'hopp'; $.each( obj, function( key, value ) { console.log($.now()); }); $.now() is the same number in the console. How can I generate a unique number? 回答1: You could have a counter which increments for each object. You could then add this counter to $.now() to make sure it's unique: obj = {}; obj[0] = 'hej'; obj[1] = 'hopp'; counter=1; $.each( obj, function( key, value ) { console.log($.now() + counter); counter+=1; }); 回答2: jQuery.now()

问题 I have a 2D Numpy array that consists of (X,Y,Z,A) values, where (X,Y,Z) are Cartesian coordinates in 3D space, and A is some value at that location. As an example.. __X__|__Y__|__Z__|__A_ 13 | 7 | 21 | 1.5 9 | 2 | 7 | 0.5 15 | 3 | 9 | 1.1 13 | 7 | 21 | 0.9 13 | 7 | 21 | 1.7 15 | 3 | 9 | 1.1 Is there an efficient way to find all the unique combinations of (X,Y), and add their values? For example, the total for (13,7) would be (1.5+0.9+1.7), or 4.1. 回答1: Approach #1 Get each row as a view,

问题 I have a constantly growing, potentially very large table in a Postgresql database that contains "data" from different "channels" for different "devices" eg.: Table data: id (PK) device_id (FK -> device) channel_id (FK -> channel) timestamp (TIMESTAMP) value (Float) I am using partitioning to separate the table into multiple subtables, one for each device, since I never need data for different devices in the same query. Since not all devices supply all channels, I would like to get a list of

问题 I have seen a variety of different methods for generating unique slugs: Ex. 1, Ex.2, Ex. 3, Ex. 4, etc. etc. I want to create unique slugs upon saving a ModelForm. If my models are like: class Phone(models.Model): user = models.ForeignKey(User) slug = models.SlugField(max_length=70, unique=True) year = models.IntegerField() model = models.ForeignKey('Model') series = models.ForeignKey('Series') Say that the Phone object has the following values (via submitted ModelForm): Phone.user = dude

问题 1) I have a table named "plan_info_upload" which is like: site_id site_name 2G_bw 3G_bw route_path 1 MBCGP1 11 30 MBLMA1>MBSMGR 2 BOPBG2 12 22 BOPBG2>BOBET16 3 BOPCB1 11 0 BOBET16>BOGBT1>BOPBG2>BOBET16 4 BOSBB1 14 25 BOSBB1>BOKDG1>BOBET16>BOGBT1 2) & another table named "hop_without_router" which is like: (divide route_path from 1st table into hop) hop_id hop_1 hop_2 hop_3..... hop_9 site_name hop_count 1 MBLMA1>MBSMGR MBCGP1 1 2 BOPBG2>BOBET16 BOPBG2 1 3 BOBET16>BOGBT1 BOGBT1>BOPBG2 BOPBG2

问题 This is my database dataset : Table ID Name XXX-23305 Edward, Stue^Jenna XXX-23305 Edward, Stue^Jenna XXX-23306 Cole, Slaw^Bali XXX-23306 Cole, Slaw^Bali XXX-23306 Cole, Slaw^Bali XXX-23310 Zerg, War^Finja XXX-23310 Road^Sieglinde XXX-23319 Gras, Dr.Carl^Yolo XXX-23319 Gras, Dr.Carl^Yolo As you can see there might be multiple entries for the same ID and Name combination. However in case of ID XXX-23310 there are two different names available. Now what I want is displaying that exact dataset (

问题 I want to count unique visitors and show them to visitors. I don't want to use any 3rd party tool (like analytics or something else) What is a unique visitor exactly? Does the REAL unique visitor changes with IP, cookie or MAC? I've though this way: Get visitors IP adress Search it from database If exists, don't do anything If not, insert IP adress and server time to database and add this to count Is this way right? Should I use cookies or get MAC adresses too? BTW all these things -getting

问题 I have a dataframe of IDs and addresses. Normally, I would expect each recurring ID to have the same address in all observations, but some of my IDs have different addresses. I want to locate those observations that are duplicated on ID, but have at least 2 different addresses. Then, I want to randomize a new ID for one of them (an ID that didn't exist in the DF before). For example: ID Address 1 X 1 X 1 Y 2 Z 2 Z 3 A 3 B 4 C 4 D 4 E 5 F 5 F 5 F Will return: ID Address 1 X 1 X 6 Y 2 Z 2 Z 3 A

问题 I have multiple machines uploading files to one FTP directory. The first part of the filename is the machine, the rest is a timestamp, e.g. AAAAA_20130312_125113. Now I want to get a sorted list of all Unique machines that have uploaded to this directory. I managed to write the lost of all filenames.substring(0,5) to the host but I still don't have the unique machine names. $files=Get-ChildItem $strMOVETO -Name -Include TAS*.csv -Recurse ForEach ($i in $files) { Write-Host $i.Substring(0,5) }