which

Regarding the .trigger() method , the Event object , the which property , the JS char codes and the code below, why does the #example input don't get the char a as auto-written value? Did I misunderstand the .trigger() method? <input type="text" name="example" id="example" value="" /> <script> $(function() { var e = jQuery.Event("keydown", { which: 65 }); $("#example").focus().trigger(e); }); </script> The mistake you're making is what you're expecting the jQuery's trigger method to do. If you check out the code you'll see that what it is doing is actually executing the jQuery registered event

I have been using the R which function to remove rows from a data frame. I recently discovered that if the search term is NOT in the data.frame, the result is an empty character. # 1: returns A-Q, S-Z (as expected) LETTERS[-which(LETTERS == "R")] # 2: returns "character(0)" (not what I would expect) LETTERS[-which(LETTERS == "1")] # 3: returns A-Z (expected) LETTERS[which(LETTERS != "1")] # 4: returns A-Q, S-Z (expected) LETTERS[which(LETTERS != "R")] Is the second example the expected behavior for -which() when the search term is not found? I have already switched my code to use the syntax in

Here is the code that I am working with: x <- c("Yes","No","No","Yes","Maybe") y <- t(1:10) z <- t(11:20) rbind.data.frame(ifelse(x == "Yes",y,z)) This produces X1L X12L X13L X4L X15L 1 1 12 13 4 15 The desired outcome is: x 1 Yes 1 2 3 4 5 6 7 8 9 10 2 No 11 12 13 14 15 16 17 18 19 20 3 No 11 12 13 14 15 16 17 18 19 20 4 Yes 1 2 3 4 5 6 7 8 9 10 5 Maybe 11 12 13 14 15 16 17 18 19 20 I was thinking that I could use an ifelse statement with the rbind.data.frame() or cbind.data.frame() function. So if x == "Yes" then that would be combined with a vector "y". As shown in the first row of the

What does ( !'which npm' ) mean in the following code? if ( !'which npm' ) { die( 'You need to install NPM!' . PHP_EOL ); } Here is a link to the complete file from GITHUB: WPBP/generator/bin/wpbp-generator deceze It checks whether a hardcoded string is falsey . Which will always be false . This logic looks a bit meaningless. I suspect the author rather wanted to write: if (!`which npm`) The backtick operator executes the command as shell command, which makes a bit more sense. 来源： https://stackoverflow.com/questions/52094786/what-does-which-npm-mean-in-a-php-script

I am trying to make a data frame with the maximum over records by a factor. I would like a data frame with 4 rows (one for each G) with the max for X in that group and the corresponding Y value. I know I could write a loop but would rather not. Data<-data.frame(X=rnorm(200), Y=rnorm(200), G=rep(c(1,2,3,4), each=50)) XMax<-tapply(Data$X, Data$G, function(x){max(x, na.rm=T)}) WhichXMax<-tapply(Data$X, Data$G, function(x){which.max(x)}) The which.max function returns the row number after the data has been subsetted by the tapply factor, where I really want the row number referencing the Data rows