parentheses

In Scala there are two ways to define a method which takes no argument 1 def a=println("hello") 2 def a()=println("hello") These two methods are exactly same but (2) can be called with and without parentheses. Is there any special reason for which this feature is allowed in Scala.It confuses me which to use and when? The general rule is that you should add an empty parameter list at both declaration site and call site whenever the method (not function) has side effects. Otherwise, Scala has the uniform access principle, so that clients don't need to know whether they're accessing a field or

Just starting to figure Python out. I've read this question and its responses: Is it true that I can't use curly braces in Python? and I still can't fathom how curly braces work, especially since pages like Simple Programs: http://wiki.python.org/moin/SimplePrograms use curly braces all over the place. I understand square brackets and regular curved parentheses, but I don't know what's meant by "defining dictionaries" or what they're supposed to represent. Brenton Alker "Curly Braces" are used in Python to define a dictionary. A dictionary is a data structure that maps one value to another -

Clearly, there are times where #define statements must have parentheses, like so: #define WIDTH 80+20 int a = WIDTH * 2; // expect a==200 but a==120 So I always parenthesize, even when it's just a single number: #define WIDTH (100) Someone new to C asked me why I do this, so I tried to find an edge case where the absence of parentheses on a single number #define causes issues, but I can't think of one. Does such a case exist? Yes . The preprocessor concatenation operator ( ## ) will cause issues, for example: #define _add_penguin(a) penguin ## a #define add_penguin(a) _add_penguin(a) #define

From http://c-faq.com/style/strcmp.html , I learned the following convenience macro: #define Streq(s1, s2) (strcmp((s1), (s2)) == 0) I want to know why there are so many parentheses being used in this macro. Is each parenthesis serving a purpose or is this macro using redundant parentheses that serve no purpose? Can we remove the parentheses around s1 and s2 and make a macro like this? #define MyStreq(s1, s2) (strcmp(s1, s2) == 0) The MyStreq macro seems to work for me as nicely as Streq . #include <string.h> #include <stdio.h> #define Streq(s1, s2) (strcmp((s1), (s2)) == 0) #define MyStreq(s1

Suppose I am given the following kind of string: "(this is (haha) a string(()and it's sneaky)) ipsom (lorem) bla" and I want to extract substrings contained within a topmost layer of parentheses. I.e. I want to obtain the strings: "this is (haha) a string(()and it's sneaky)" and "lorem" . Is there a nice pythonic method to do this? Regular expressions are not obviously up to this task, but maybe there is a way to get an xml parser to do the job? For my application I can assume the parentheses are well formed, i.e. not something like (()((). This is a standard use case for a stack: You read the

I am trying to find all possible word/tag pairs or other nested combinations with python and its regular expressions. sent = '(NP (NNP Hoi) (NN Hallo) (NN Hey) (NNP (NN Ciao) (NN Adios)))' def checkBinary(sentence): n = re.findall("\([A-Za-z-0-9\s\)\(]*\)", sentence) print(n) checkBinary(sent) Output: ['(NP (NNP Hoi) (NN Hallo) (NN Hey) (NNP (NN Ciao) (NN Adios)))'] looking for: ['(NP (NNP Hoi) (NN Hallo) (NN Hey) (NNP (NN Ciao) (NN Adios)))', '(NNP Hoi)', '(NN Hallo)', '(NN Hey)', '(NNP (NN Ciao) (NN Adios))', '(NN Ciao)', '(NN Adios)'] I think the regex formula could find the nested