arguments

问题 Can I have a method which takes arguments that are denoted with the same names as the members of the holding class? I tried to use this: class Foo { public: int x, y; void set_values(int x, int y) { x = x; y = y; }; }; ... but it doesn't seem to work. Is there any way of accessing the the instance the namespace of which I'm working in, similar to JavaScript's this or Python's self ? 回答1: It's generally a good idea to avoid this kind of confusion by using a naming convention for member

问题 I have some files: dir/foo.txt dir/bar.txt dir/foobar.txt In an Ant apply task, I want to pass the list of files as arguments: <target name="atask"> <apply executable="${cmd}" parallel="false" verbose="true"> <arg value="-in"/> <srcfile/> <arg value="dir/foo.txt"/> <arg value="dir/bar.txt"/> <arg value="dir/foobar.txt"/> <fileset dir="${list.dir}" includes="*.list"/> </apply> </target> This works fine, but what if I want to pick the list of files dynamically, using a fileset: <fileset dir=

问题 I'm making a small program in C that deals with a lot of command line arguments, so I decided to use getopt to sort them for me. However, I want two non-option arguments (source and destination files) to be mandatory, so you have to have them as arguments while calling the program, even if there's no flags or other arguments. Here's a simplified version of what I have to handle the arguments with flags: while ((c = getopt(argc, argv, "i:d:btw:h:s:")) != -1) { switch (c) { case 'i': { i = (int

问题 I am using Ruby on Rails 3 and I would like to know what means the presence of a * operator near a function argument and to understand its usages in others scenarios. Example scenario (this method was from the Ruby on Rails 3 framework): def find(*args) return to_a.find { |*block_args| yield(*block_args) } if block_given? options = args.extract_options! if options.present? apply_finder_options(options).find(*args) else case args.first when :first, :last, :all send(args.first) else find_with

问题 Say I have an array. I wish to pass the array to a function. The function, however, expects two arguments. Is there a way to on the fly convert the array into 2 arguments? For example: a = [0,1,2,3,4] b = [2,3] a.slice(b) Would yield an error in Ruby. I need to input a.slice(b[0],b[1]) I am looking for something more elegant, as in a.slice(foo.bar(b)) Thanks. 回答1: You can turn an Array into an argument list with the * (or "splat") operator: a = [0, 1, 2, 3, 4] # => [0, 1, 2, 3, 4] b = [2, 3]

问题 As this function can take unknown numbers of parameters: function BulkParam(){ return func_get_args(); } A print_r will print only the values, but how i can retrieve the variable names as well as the array key? For example: $d1 = "test data"; $d2 = "test data"; $d3 = "test data"; print_r(BulkParam($d1, $d2, $d3)); It will print this: Array ( [0] => test data [1] => test data [2] => test data ) But i want to have the variables name as the index name or key name of all arrays. Then the array

问题 This question already has answers here : What does ** (double star/asterisk) and * (star/asterisk) do for parameters? (20 answers) Closed 4 years ago . I'm passing a lot data around; specifically, I'm trying to pass the output of a function into a class and the output contains a tuple with three variables. I can't directly pass the output from my function (the tuple) into the class as in the input parameters. How can format the tuple so it is accepted by the class without input_tuple[0],

问题 Part of the GUI I'm building using tkinter has a pop-up window that says "Please wait while the program is running." then after it finishes the window goes away. I'm using the widget.after command to open the window and run the command. However if I pass the function I call arguments then the pop up window never occurs. Here's an example: def backupWindow self.restoreCB = Toplevel() message = "Please wait while backup runs" Label(self.restoreCB, text=message, padx=100, pady=20).pack() widget

问题 This question already has answers here : Is there a way to set a default parameter equal to another parameter value? (4 answers) Closed 4 years ago . Is it possible to define a function argument's default value to another argument in the same function definition? Something like: def func(a, b=a): print a, b but that didn't work. 回答1: No. This is not possible. The Python interpreter thinks that you want to assign the default value of argument b to a global variable a when there isn't a global

问题 It will look like int main(int argc, char *argv[]); . My questions are: 1 How many array items can I add in argv[] ? 2 What is MAX size of every char * ? 回答1: You can try: $ getconf ARG_MAX 2180000 http://pubs.opengroup.org/onlinepubs/007904975/basedefs/limits.h.html ARG_MAX is maximum length of argument to the exec functions including environment data. That is, there is no individual limit on the number of arguments or argument's length. Only the limit on total size required to store all the