hash

问题 Is there a hash function with following properties? is associative is not commutative easily implementable on 32 bit integers: int32 hash(int32, int32) If I am correct, such function allows achieving following goals calculate hash of concatenated string from hashes of substrings calculate hash concurrently calculate hash of list implemented on binary tree - including order, but excluding how tree is balanced The best I found so far is multiplication of 4x4 matrix of bits, but thats awkward to

问题 I'm currently developing a tool that would allow me to modify the md5 of a zip file. The directory structure of the file looks like baselines-> models -> icons -> lang -> (a bunch of files here) However, when I run my code, none of those directories are getting iterating into. The output gives me: Name:model/visualization_dependency.xml Name:model/visualization_template.xml Name:model/weldmgmt_dependency.xml Name:model/weldmgmt_template.xml I was expecting to something like model/baseline

问题 I'm wondering what a location or rewrite nginx directive for hashbang (#!) urls would look like. Basically routing all non hash-banged url's through the hashbang like a front controller. So: http://example.com/about/staff would route to http://example.com/#!/about/staff I'm unclear what the best technique here would be? Whether writing an if statement to check existence of the hashbang, or just a generic rewrite that filters all requests... 回答1: GETs for fragment identifiers don't/shouldn't

问题 I have a scalar $subscribers that could be undef, reference to a HASH, or reference to an ARRAY. I have assigned the sample values $VAR1 , $VAR2 and $VAR3 for testing. I'm only interested in $subscribers when it is a reference to an ARRAY, where by it would contain multiple values. In other cases, I'm not interested in printing anything (e.g. when $subscribers=$VAR2; The code seems to run fine under Perl v5.16.2; however, when I move it to the target machine running Perl v5.8.8, I get a

问题 I am new in PHP Development. Today I came across the interesting topic URL fragmentation specifically the '#' part of the URLs. I searched about that It says it's like www.example.com\foo.html#bar. But I don't understand why this "#bar" is needed. and how to read it by PHP? 回答1: A fragment is an internal page reference, sometimes called a named anchor. It usually appears at the end of a URL and begins with a hash (#) character followed by an identifier. It refers to a section within a web

问题 I can't figure out how to create a filter or tag in a jekyll plugin, so that I can return a directory and loop over its contents. I found these: http://pastebin.com/LRfMVN5Y http://snippets.dzone.com/posts/show/302 So far I have: module Jekyll class FilesTag < Liquid::Tag def initialize(tag_name, text, tokens) super @text = text end def render(context) #"#{@text} #{Time.now}" Dir.glob("images/*").each { |i| "#{i}" } #Dir.glob("images/*") #Hash[*Dir.glob("images/*").collect { |v| [v, v*2] }

问题 A splat on a hash converts it into an array. [*{foo: :bar}] # => [[:foo, :bar]] Is there some hidden mechanism (such as implicit class cast) going on here, or is it a built-in primitive feature? Besides an array, are nil and hash the only things that disappear/change with the splat operator under Ruby 1.9? 回答1: A splat will attempt an explicit conversion of an object to an Array. To do this, it will send to_a and expect an Array as a result. class Foo def to_a [1,2,3] end end a, b, c = *Foo

问题 I'm just curious as to why this choice was made - it basically rules out changing the compression algorithm used by Git - because it doesn't use the SHA1 of the raw blobs. Perhaps there is some efficiency consideration here. Maybe ZLIB is faster at compressing a file than the SHA1 algorithm is at creating the hash, so therefore compressing before hashing is faster? Here is a link to the original Git READMEby Linus: http://git.kernel.org/?p=git/git.git;a=blob;f=README;h

问题 I'm just curious as to why this choice was made - it basically rules out changing the compression algorithm used by Git - because it doesn't use the SHA1 of the raw blobs. Perhaps there is some efficiency consideration here. Maybe ZLIB is faster at compressing a file than the SHA1 algorithm is at creating the hash, so therefore compressing before hashing is faster? Here is a link to the original Git READMEby Linus: http://git.kernel.org/?p=git/git.git;a=blob;f=README;h

问题 on this page: http://www.shutterfly.com/documentation/OflyCallSignature.sfly it says once you generate a hash you then: convert the hash to a hexadecimal character string is there code in csharp to do this? 回答1: To get the hash, use the System.Security.Cryptography.SHA1Managed class. EDIT : Like this: byte[] hashBytes = new SHA1Managed().ComputeHash(Encoding.UTF8.GetBytes(str)); To convert the hash to a hex string, use the following code: BitConverter.ToString(hashBytes).Replace("-", ""); If