I want to make an array containing three wide character arrays such that one of them is the key.
"LPWCH,LPWCH,LPWCH" was not able to use the greater than/lesser than symbols since it thinks it is a tag
Hash_map only lets me use a pair. wKey and the element associated with it. Is there another data structure that lets me use this?
This set will be updated by different threads almost simultaneously. And thats the reason why I don't want to use a class or another struct to define the remaining two wide character arrays.
You can use LPWCH as a key and std::pair<LPWCH, LPWCH> as an element.
Using any of LP-typedefs is not good. You would only be comparing the points, and not strings.
LPWCH is nothing but a WCHAR* which can be drilled down to void*. When you compare two pointers, you are comparing where they are pointing, and not what they are pointing.
You either need to have another comparer attached to your map/hash_map, or use actual string datatype (like std::string, CString)
Related
I'm about to compare to string of equal length. Then I need to count the differences they have. I would start doing that by hand - but since there is such a toolbox of methods I wonder if there is a function that may count the differences that occured anyhow? Or create a collection which I can count the elements in?
You can use the strsim crate. It offers various string difference methods like Hamming, Levenshtein, Damerau-Levenshtein, Jaro, and Jaro-Winkler. I personally like the Damerau-Levenshtein difference, which counts the number of adjacent characters you need to swap and the number of characters you need to remove, insert or replace to turn one of the strings into the other.
extern crate strsim;
let difference = strsim::damerau_levenshtein(a, b);
Implementation of Hamming distance is trivial:
str_a.chars().zip(str_b.chars()).filter(|x| x.0!=x.1).count()
How do I get numeric values from the RepresentationModel?
Say, after traversing a document, I have a YamlScalarNode. It has a string Value, which I can, of course, try to convert to a number, but I'd expect YAML to detect the type and present it as int or double etc. (perhaps via descendants from YamlScalarNode, whose type I could detect).
Is there an official way to do it that I'm missing?
Note that I can't use Serialization: the document structure does not directly map to a class; it can be a recursive definition of arbitrary depth, and the end values are either scalar numbers or sequences of numbers (vectors).
Also, can YamlDotNet handle numerical keys in mappings? This means that keys 1 and 01 should be considered duplicates. I believe YAML specification requires that, but I'm not certain...
The YAML schemas specify how scalars are to be interpreted. Ideally, you would look at the tag of a scalar to establish its type according to the selected schema. However, YamlDotNet does not yet implement them. For now you will have to do that yourself.
The main problem is that I'm working in a functional language with immutable types so thing like pointers and deletion are a bit harder. I would prefer if this was implementable primarily in Haskell.
Let's imagine we have a single dimensional field
[x,x,x,x,x,x,x,x,x]
So I have a map with keys being SIZES and values being ADDRESSES because each entry starts from a certain ADDRESS and has a certain SIZE.
[(x,x,x),x,x,(x,x,x,x)]
I want to be able to add an element by SIZE to a map and then check if the entries are touching so that I can merge them.
Since my map is by SIZEs I have to iterate through the whole map to find the ones with the bordering ADDRESSes.
Do I really have to chose between implementing a 2 key map and O(n) for merger?
Welp, in essence, this looks like computer memory. Do you want it to be efficient? Because you know, "things like pointers" exist and work in Haskell perfectly well.
Since my map is by SIZEs I have to iterate through the whole map to find the ones with the bordering ADDRESSes.
No, if you store the ranges in a separate data structure. I think for such non-overlapping subsets, there was something called a spanning tree (or as suggested by #Daniel, IntervalMap), but I'm not exactly an expert on those. Otherwise, why don't you simply hold memory blocks like that?
data Block = Block { start :: Int, data :: [Byte] }
type Memory = [Block]
You could cache the block length or use a data structure where length is O(1), to make merges O(nBlocks).
Sure, that doesn't make it obvious at the type level that they won't ever overlap, but that's an invariant you can keep for yourself.
I am receiving as input a "map" represented by strings, where certain nodes of the map have significance (s). For example:
---s--
--s---
s---s-
s---s-
-----s
My question is, what reasonable options are there for representing this input as an object.
The only option that really comes to mind is:
(1) Each position translated to node with up,down,left,right pointers. The whole object contains a pointer to top right node.
This seems like just a graph representation specific to this problem.
Thanks for the help.
Additionally, if there are common terms for this type of input, please let me know
Well, it depends a lot on what you need to delegate to those objects. OOP is basically about asking objects to perform things in order to solve a given problem, so it is hard to tell without knowing what you need to accomplish.
The solution you mention can be a valid one, as can also be having a matrix (in this case of 6x5) where you store in each matrix cell an object representing the node (just as an example, I used both approaches once to model the Conway's game of life). If you could give some more information on what you need to do with the object representation of your map then a better design can be discussed.
HTH
I have come across Tuples in net 4.0. I have seen few example on msdn,however it's still not clear to me about the purpose of it and when to use them.
Is it the idea that if i want to create a collections of mix types I should use a tuple?
Any clear examples out there I can relate to?
When did you last use them?
Thanks for any suggestions
Tuples are just used on the coding process by a developer. If you want to return two informations instead of one, then you can use a Tuple for fast coding, but I recoment you make yourself a type that will contain both properties, with appropriate naming, and documentation.
Tuples are not used to mix types as you imagine. Tuples are used to make compositions of other types. e.g. a type that holds both an int and a string can be represented by a tuple: Tuple<int,string>.
Tuples exists in a lot of sizes, not only two.
I don't recommend using tuples in your final code, since their meaning is not clear.
Tuples can be used as multipart keys for dictionaries or grouping statements because being value types they understand equality. Avoid using them to move data around because they have poor language support in C# and named values (classes, structs) are better (simpler) than ordered values (tuples).