When I am running the following statement: @filtered = map {s/ //g} @outdata; it is returning an empty list instead of the filtered list that I expected. What I am trying to do is remove every occurance of from an array of string (which is an XML file). Obviously, I am not understanding something. Can anyone tell me the...
If I have an object implementing the Map interface in Java and I wish to iterate over every pair contained within it, what is the most efficient way of going through the map? Will the ordering of elements depend on the specific map implementation that I have for the interface? ...
I'm specifically looking for one that lets me display a map of US states with each one as it's own "object" in the sense that I can control the color, on click, and on mouseover of each one individually. GTK is my personal preference, but at this point I'd settle for just about anything. The application itself will be written in Python...
I want something like an std::map, but I only want to see if the item exists or not, I don't actually need a key AND value. What should I use? ...
I usually use C++ STL map whenever I need to store some data associated with a specific type of value (a key value - e.g. a string or other object). The STL map implementation is based on trees which provides better performance (O(log n)) than the standard array or STL vector. My questions is, do you know of any C++ "standard" hashtable...
Not really getting the point of the map function. Can anyone explain with examples its use? Are there any performance benefits to using this instead of a loop or is it just sugar? ...
Do you know any easy or simple way to make a map object (from the STL library) persistent (i.e. write it to a file) so that you can recover its state later when the program in run later ?? Thanks for your help ...
Assume I have a class foo, and wish to use a std::map to store some boost::shared_ptrs, e.g.: class foo; typedef boost::shared_ptr<foo> foo_sp; typeded std::map<int, foo_sp> foo_sp_map; foo_sp_map m; If I add a new foo_sp to the map but the key used already exists, will the existing entry be deleted? For example: foo_sp_map m; vo...
I'm building a shared library with g++ 3.3.4. I cannot link to the library because I am getting ./BcdFile.RHEL70.so: undefined symbol: _ZNSt8_Rb_treeIjjSt9_IdentityIjESt4lessIjESaIjEE13insert_uniqueERKj Which c++filt describes as std::_Rb_tree<unsigned int, unsigned int, std::_Identity<unsigned int>, std::less<unsigned int>, std::a...
what is a good way to select a random element from a map? C++. It is my understanding that maps don't have random access iterators. The key is a long long and the map is sparsely populated. ...
Is there a good way to have a Map get and put ignore case? ...
I want to have a map that has a homogeneous key type but heterogeneous data types. I want to be able to do something like (pseudo-code): boost::map<std::string, magic_goes_here> m; m.add<int>("a", 2); m.add<std::string>("b", "black sheep"); int i = m.get<int>("a"); int j = m.get<int>("b"); // error! I could have a pointer to a base ...
ExtJS has Ext.each() function, but is there a map() also hidden somewhere? I have tried hard, but haven't found anything that could fill this role. It seems to be something simple and trivial, that a JS library so large as Ext clearly must have. Or when Ext really doesn't include it, what would be the best way to add it to Ext. Sure, I...
I'm trying to figure out if there's a reasonably efficient way to perform a lookup in a dictionary (or a hash, or a map, or whatever your favorite language calls it) where the keys are regular expressions and strings are looked up against the set of keys. For example (in Python syntax): >>> regex_dict = { re.compile(r'foo.') : 12, re.c...
I need to write the content of a map (key is ID of int, value is of self-defined struct) into a file, and load it from the file later on. Can I do it in MFC with CArchive? Thank you! ...
My web service method returns a Page object which includes the following methods: public Map<String,String[]> getParameters() { ... } public setParameters(Map<String,String[]> parameters) { ... } On the client side, the JAX-WS generated getParameters() method returns a Parameters object which provides a getEntry() method that returns ...
Duplicate: What happens if you call erase on a map element while iterating from begin to end How to filter items from a stdmap I have a map map1<string,vector<string>> i have a iterator for this map "itr". i want to delete the entry from this map which is pointed by "itr". i can use the function map1.erase(itr); after this lin...
In Python map() works on any data that follows the sequence protocol. It does The Right Thing^TM whether I feed it a string or a list or even a tuple. Can't I have my cake in OCaml too? Do I really have no other choice but to look at the collection type I'm using and find a corresponding List.map or an Array.map or a Buffer.map or a S...
This fails: my @a = ("a", "b", "c", "d", "e"); my %h = map { "prefix-$_" => 1 } @a; with this error: Not enough arguments for map at foo.pl line 4, near "} @a" but this works: my @a = ("a", "b", "c", "d", "e"); my %h = map { "prefix-" . $_ => 1 } @a; why? ...
I've got three (relevant) models, specified like this: class User < ActiveRecord::Base has_many :posts has_many :comments has_many :comments_received, :through => :posts, :source => :comments end class Post < ActiveRecord::Base belongs_to :user has_many :comments end class Comment < ActiveRecord::Base belongs_to :user be...