hash

问题 I know that in Ruby you can create hash maps like this: hash = {"name"=>"John"} But is it possible to have a hash map of methods: hash = {"v"=> show_version} and when calling hash["v"] either to execute the show_version function, or to return some kind on pointer that passed to some special method, to execute the function from the hash? What I am trying to achieve, is to have a hash map of methods, instead of using a case/when construction, as it looks too verbose to me. 回答1: Not exactly like

问题 I am writing a method to generate cache keys for caching function results, the key is based on a combination of function name and hash value of parameters. Currently I am using hashlib to hash the serialized version of parameters, however the operation is very expensive to serialize large objects, so what's the alternative? #get the cache key for storage def cache_get_key(*args): import hashlib serialise = [] for arg in args: serialise.append(str(arg)) key = hashlib.md5("".join(serialise))

问题 I am looking for a way to generate some kind of hash for PHP object (generic solution, working with all classed, built-in and custom, if possible). SplObjectStorage::getHash is not what I'm looking for, as it will generate different hash for every instance of given class. To picture the problem, let's consider simple class: class A() { public $field; //public only for simplicity } and 2 instances of that class: $a = new A(); $a->field = 'b'; $b = new A(); $b->field = 'b'; Every built-in

问题 I have a database-driven web application where the primary keys of all data rows are obfuscated as follows: SHA256(content type + primary key + secret), truncated to the first 8 characters. The content type is a simple word, e.g. "post" or "message" and the secret is a 20-30 char ASCII constant. The result is stored in a separate indexed column for fast DB lookup. How do I calculate the probability of a hash collision in this scenario? I am not a mathematician at all, but a friend claimed

问题 I need to hash a message into a string of 30 chars. What's the best and most secure hash function for this usage? 回答1: Thirty characters (bytes) is 240 bits. If you can't move the goal-post to allow 32 characters, then you will probably end up using SHA-1, which generates 160-bits or 20 bytes. When Base-64 encoded, that will be 28 characters. If you use a hex-encoding, it will be 40 characters, which is nominally out of range. With 32 characters, you could use SHA-256, but Base-64 encoding

问题 I need to hash a message into a string of 30 chars. What's the best and most secure hash function for this usage? 回答1: Thirty characters (bytes) is 240 bits. If you can't move the goal-post to allow 32 characters, then you will probably end up using SHA-1, which generates 160-bits or 20 bytes. When Base-64 encoded, that will be 28 characters. If you use a hex-encoding, it will be 40 characters, which is nominally out of range. With 32 characters, you could use SHA-256, but Base-64 encoding

问题 I need to hash a message into a string of 30 chars. What's the best and most secure hash function for this usage? 回答1: Thirty characters (bytes) is 240 bits. If you can't move the goal-post to allow 32 characters, then you will probably end up using SHA-1, which generates 160-bits or 20 bytes. When Base-64 encoded, that will be 28 characters. If you use a hex-encoding, it will be 40 characters, which is nominally out of range. With 32 characters, you could use SHA-256, but Base-64 encoding

问题 friends. I'm trying to write code that hashes all values in a JSON file, regardless of file structure, while preserving the keys and structure. I'm new to javascript, and am having some trouble. My code hashes the values of big and baz, but doesn't recursively hash the values of cat and bar like I want it to. Ideally, I want the numbers hashed and the names (big, foo, etc.) left alone. Thank you so much! See my code below: var meow = { big: 20, baz: { foo: { cat: 3, bar: 5 } } }; console.log

问题 I have a hash containing node data. I am expecting hash content to be printed in -r_<count> and -d_<count> attributes. Here is the script: use strict; use warnings; use Data::Dumper; my %hash = ( 'Network=Test,Cell=31' => [ 'Network=Test,Unit=RU-1-1,Port=A', 'Network=Test,Unit=RU-1-2,Port=A' ], 'Network=Test,Cell=32' => [ 'Network=Test,Unit=RU-1-1,Port=A', 'Network=Test,Unit=RU-1-2,Port=A' ], 'Network=Test,Cell=33' => [ 'Network=Test,Unit=RU-1-5,Port=A', 'Network=Test,Unit=RU-1-6,Port=A' ], )

问题 I have a hash containing node data. I am expecting hash content to be printed in -r_<count> and -d_<count> attributes. Here is the script: use strict; use warnings; use Data::Dumper; my %hash = ( 'Network=Test,Cell=31' => [ 'Network=Test,Unit=RU-1-1,Port=A', 'Network=Test,Unit=RU-1-2,Port=A' ], 'Network=Test,Cell=32' => [ 'Network=Test,Unit=RU-1-1,Port=A', 'Network=Test,Unit=RU-1-2,Port=A' ], 'Network=Test,Cell=33' => [ 'Network=Test,Unit=RU-1-5,Port=A', 'Network=Test,Unit=RU-1-6,Port=A' ], )