parameter-passing

问题 With prototypes, you can create a subroutine that accepts a block of code as its first parameter: sub example (&) { my $code_ref = shift; $code_ref->(); } example { print "Hello\n" }; How can I do the same thing, but with more than one block of code? I want to use blocks of codes, not variables or sub { ... } . This does not work: sub example2 (&&) { my $code_ref = shift; my $code_ref2 = shift; $code_ref->(); $code_ref2->(); } example2 { print "One\n" } { print "Hello\n" }; It gives this

问题 With prototypes, you can create a subroutine that accepts a block of code as its first parameter: sub example (&) { my $code_ref = shift; $code_ref->(); } example { print "Hello\n" }; How can I do the same thing, but with more than one block of code? I want to use blocks of codes, not variables or sub { ... } . This does not work: sub example2 (&&) { my $code_ref = shift; my $code_ref2 = shift; $code_ref->(); $code_ref2->(); } example2 { print "One\n" } { print "Hello\n" }; It gives this

问题 These are my 2 Forms. These are the codes for Form 1--> namespace Passing_Values { public partial class Form1 : Form { string a="preset value"; public Form1() { InitializeComponent(); } private void btnOpenF2_Click(object sender, EventArgs e) { new Form2().Show(); } public void set(string p) { MessageBox.Show("This is Entered text in Form 2 " + p); a = p; MessageBox.Show("a=p done! and P is: " + p + "---and a is: " + a); textBox1.Text = "Test 1"; textBox2.Text = a; textBox3.Text = p; }

问题 These are my 2 Forms. These are the codes for Form 1--> namespace Passing_Values { public partial class Form1 : Form { string a="preset value"; public Form1() { InitializeComponent(); } private void btnOpenF2_Click(object sender, EventArgs e) { new Form2().Show(); } public void set(string p) { MessageBox.Show("This is Entered text in Form 2 " + p); a = p; MessageBox.Show("a=p done! and P is: " + p + "---and a is: " + a); textBox1.Text = "Test 1"; textBox2.Text = a; textBox3.Text = p; }

问题 I have the following issue: I have designed a framework that uses a generic delegate function (Func<...>) to calculate distance between two real number vectors The delegate has the following form: Func<double[], double[], double> distance; I have many different distance functions implemented I would rather not change the signature of distance delegate I need to create a new function that besides two double vectors needs some additional parameters i.e. Func<double[], double[], double, double,

问题 In PostgreSQL 9.1, PL/pgSQL, given a query: select fk_list.relname from ... where relname is of type name (e.g., "table_name"). How do you get the appropriate value for "relname" that can be used directly in an UPDATE statement as: Update <relname> set ... within the PL/pgSQL script? Using quote_ident(r.relname) as: Update quote_ident(r.relname) Set ... fails with: syntax error at or near "(" LINE 55: UPDATE quote_ident(r.relname) .... The complete code I am working with: CREATE FUNCTION

问题 I asked a similar question earlier without realizing that that wasn't quite specific enough. So I have this function that has to take in all the arguments of a print function, with the ... and all, and then put it into a queue that will call the actual print function later. Something like: std::queue<SOMETHING> queue; template <typename... Params> void printLater(int a, int b, char* fmt, Params ...args) { queue.push(args); } template <typename... Params> void print(int a, int b, char* fmt,

问题 While trying to pass an user entered input (empId) from Shiny UI into a sql query on shiny server.r not sure how to debug this error. Error in as.vector(x, "character") : cannot coerce type 'closure' to vector of type 'character' UI.r library(shiny) shinyUI(fluidPage( titlePanel("Employee Table (AdventureWorks)"), sidebarLayout( sidebarPanel((""), textInput("idnumb", "Employee ID number",""), submitButton("Ok")), mainPanel(tableOutput("emptitle"))))) Server.r shinyServer(function(input,

问题 I have a function that takes as parameters an input folder (required) and output folder (optional), but I want the default value of the (optional) output folder to be the input folder. I can do this of course using, e.g. p = argparse.ArgumentParser(description="blah") p.add_argument('inpath', type=str, help="Path to input") p.add_argument('--outpath', required=False, type=str, help="Path to output") argin = p.parse_args() if argin.outpath is None: argin.outpath = argin.inpath but I want to

问题 void restartWeb() { try { String[] command = new String[] {"webRestarter.exe" , ">>","webLog.log"}; Runtime.getRuntime().exec(command); } catch (java.io.IOException err) { webServer.logError(err.getMessage()); } } Why doesn't this work? How could I fix it so it does work like I want it to? -- Executes webRestarter.exe with parameters >>webLog.log So it'd spit out something like this: webRestarter.exe>>webLog.log 回答1: You simply can't use pipes in a exec call. Pipes are a functionality of the