max

问题 I am working on a time series data. I have 2 date time columns and 1 fiscal week column. I have given an example where I have a situation like below and I need to get the MAX of the EditDate. EditDate <- c("2015-04-01 11:40:13", "2015-04-03 02:54:45","2015-04-07 11:40:13") ID <- c("DL1X8", "DL1X8","DL1X8") Avg <- c(38.1517, 38.1517, 38.1517) Sig <- c(11.45880000, 11.45880000, 11.45880000) InsertDate <- c("2015-04-03 9:40:00", "2015-04-03 9:40:00",2015-04-10 9:40:00) FW <- c("39","39","40")

问题 What limit should be placed on the number of rows to delete in a SQL statement? We need to delete from 1 to several hundred thousand rows and need to apply some sort of best practise limit in order to not absolutely kill the SQL server or fill up the logs every time we empty a waste-basket. This question is not specific to any type of database. 回答1: That's a very very broad question that basically boils down to "it depends". The factors that influence it include: What is your level of

问题 I work at a nanotech lab where I do silicon wafer dicing. (The wafer saw cuts only parallel lines) We are, of course, trying to maximize the yield of the die we cut. All the of die will be equal size, either rectangular or square, and the die are all cut from a circular wafer. Essentially, I am trying to pack maximum rectangles into a circle. I have only a pretty basic understanding of MATLAB and an intermediate understanding of calculus. Is there any (relatively) simple way to do this, or am

问题 I've managed to find the minimum value of every row of my 2D array with this void findLowest(int A[][Cm], int n, int m) { int min = A[0][0]; for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { if (A[i][j] < min) { min = A[i][j]; } } out << i << " row's lowest value " << min << endl; } } I'am trying to find the maximum value of every row using the same way,but it only shows me first maximum value void findHighest(int A[][Cm], int n, int m) { int max = A[0][0]; for (int i = 0; i < n; i+

问题 which.max and which.min will return the smallest index of the max or min value if there are ties. Is there a way around this so that the largest index is returned without affecting the efficiency of the function? max.col has this exact functionality, but I am dealing with a vector not a matrix. 回答1: You could do like this: x<-c(1,2,1,4,3,4) #identical to which.max, except returns all indices with max which(x==max(x)) [1] 4 6 z<-which(x==max(x)) z[length(z)] [1] 6 #or with tail tail(which(x=

问题 I am trying to get max value from a 3-d Mat, but minmaxIdx and mixmaxloc both failed to do this. int sz[] = {BIN, BIN, BIN}; Mat accumarray(3, sz, CV_8U, Scalar::all(0)) ; double testMaxval = 0; int minIdx = accumarray.dims ; minMaxIdx(accumarray, NULL, &testMaxval,NULL,minIdx ,NULL) ; cout<<testMaxval<<endl ; This code wouldn't work, so Can I use max(), minmaxidx(), or minmaxloc() to get the max value efficiently without manually process the entire n-dimensional array? 回答1: Following code

问题 For example: name | weight jon 100 jane 120 joe 130 How do I only return the name of the person with the largest weight? 回答1: Use this: select name from tbl where weight = (select max(weight) from tbl) 回答2: SELECT name FROM tbl ORDER BY weight DESC LIMIT 1 Much more performant than the other answer and results in one row only. 回答3: ORDER BY DESC puts rows with null values at the top. To avoid returning results corresponding to null values : SELECT name FROM tbl WHERE weight = (SELECT MAX

问题 I've got this matrix: a <- matrix(rnorm(1000 * 18, mean = 100, sd = sqrt(10)), 1000, 18) I would like to find the maximum and minimum value of every column and the maximum and minimum value of every row. 回答1: Figured it out. Minimum and maximum of every column: apply(a,2,min) apply(a,2,max) Minimum and maximum of every row: apply(a,1,min) apply(a,1,max) Found the information here http://www.personality-project.org/r/r.commands.html 回答2: See the matrixStats package. You can use colMins() ,

问题 I've got this matrix: a <- matrix(rnorm(1000 * 18, mean = 100, sd = sqrt(10)), 1000, 18) I would like to find the maximum and minimum value of every column and the maximum and minimum value of every row. 回答1: Figured it out. Minimum and maximum of every column: apply(a,2,min) apply(a,2,max) Minimum and maximum of every row: apply(a,1,min) apply(a,1,max) Found the information here http://www.personality-project.org/r/r.commands.html 回答2: See the matrixStats package. You can use colMins() ,

问题 I need to find the indices of the k largest elements of an unsorted, length n, array/vector in C++, with k < n. I have seen how to use nth_element() to find the k-th statistic, but I'm not sure if using this is the right choice for my problem as it seems like I would need to make k calls to nth_statistic, which I guess it would have complexity O(kn), which may be as good as it can get? Or is there a way to do this just in O(n)? Implementing it without nth_element() seems like I will have to