conditional

问题 I'm trying to create a data.frame that takes different values depending on the value of a reference data.frame. I only know how to do this with a "for loop", but have been advised to avoid for loops in R... and my actual data have ~500,000 rows x ~200 columns. a <- as.data.frame(matrix(rbinom(10,1,0.5),5,2,dimnames=list(c(1:5),c("a","b")))) b <- data.frame(v1=c(2,10,12,5,11,3,4,14,2,13),v2=c("a","b","b","a","b","a","a","b","a","b")) c <- as.data.frame(matrix(0,5,2)) for (i in 1:5){ for(j in 1

问题 Any way to configure eclipse to only wrap if statements in braces if it is multiple lines, and leave alone single line statements? e.g. if (x == y) z(); if (x == y){ z(); } 回答1: How would it know? If you have a default of always using braces for multiple or single, you will avoid errors of putting in code that is supposed to be part of the if statement but ends up not. 回答2: Use can use //formatter:off and //formatter:on tags to switch on or switch off formatting in a given range of code lines

问题 I am implementing some methods which use switch statements to distinguish between different cases: private void doThis(){ switch(command){ case on: {status = doCalculationsA; break;} case off: {status = doCalculationsB; break;} case idle: {status = doCalculationsC; break;} case stdby:{status = doCalculationsD; break;} } } The above works fine, when, further down the business logic, I call doThis() inside other methods which need the doThis() functionality. However, at this moment I am a bit

问题 i'm trying to throw together a simple javascript page with multiple if statements. the idea is to append to a list based on the evaluation of a stack of if statements. the problem is if any one of them fails, it triggers the else statement. i only want it to trigger else in the case that all of them fail. <p id="fruit">My fruit basket has: </p> if (apples) { document.getElementById("fruit").innerHTML += "apples"; } if (oranges) { document.getElementById("fruit").innerHTML += "oranges"; } if

问题 I have VBA code that works, but does not seem to be optimal. The code should change the colour of the text in the relevant cell in columns H & I when a cell in Column N is clicked. For example, when cell N5 is clicked, the text in cells H5 and I5 should turn white. When it is unclicked, they return to their normal colour. The code does not seem to be optimal because the change in column I lags behind that in column H. I would like a way to make both change instantaneously. (Bonus points if

问题 I currently have a long if statement, which looks ugly, and I'm fairly certain isn't proper. It looks something like this. if self.folderactive.isChecked: folders.createDir('Desktop') elif not self.folderactive.isChecked: folders.deleteDir('Desktop') if self.folderactive_2.isChecked: folders.createDir('Documents') elif not self.folderactive_2.isChecked: folders.deleteDir('Documents') if self.folderactive_3.isChecked: folders.createDir('Downloads') elif not self.folderactive_3.isChecked:

问题 I am performing an ADF-test from statsmodels. The value series can have missing obversations. In fact, I am dropping the analysis if the fraction of NaNs is larger than c. However, if the series makes it through the I get the problem, that the adfuller cannot deal with missing data. Since this is training data with a minimum framesize, I would like to do: 1) if x(t=0) = NaN, then find the next non-NaN value (t>0) 2) otherwise if x(t) = NaN, then x(t) = x(t-1) So I am compromising here my

问题 I am performing an ADF-test from statsmodels. The value series can have missing obversations. In fact, I am dropping the analysis if the fraction of NaNs is larger than c. However, if the series makes it through the I get the problem, that the adfuller cannot deal with missing data. Since this is training data with a minimum framesize, I would like to do: 1) if x(t=0) = NaN, then find the next non-NaN value (t>0) 2) otherwise if x(t) = NaN, then x(t) = x(t-1) So I am compromising here my

问题 This question already has answers here : c++ bool question [duplicate] (2 answers) Closed 4 years ago . I've seen code where a condition is evaluated based on an int variable instead of bool. int condition cin >> condition; if (!condition) //do something I know that C++ supports that 0 is false and 1 is true, but is this safe code? Is it supported by all C++ compilers as a standard? Could it also be a bad practice considering that you might switch to another language and find out that this

问题 I am just curious if this is possible or is there a way for this to become a valid syntax for C#: expression == value ? /*do nothing here, or put some empty block like { ; } */ : SomeClass.SomeMethod(); Edit : For an in-depth discussion and more information, I thought this block would work (if the dictionary key tested does not exist, it adds the dictionary. else, it would skip): (!packageDict.ContainsKey(desc)) ? packageDict.Add(desc, subtotal) : /*does nothing*/; 回答1: By looking at your