You can do this with a lambda: extract_keyname = ->(h) { h[:keyname] } ary_of_hashes.map(&extract_keyname) This tends to be more useful if the block’s logic is more complicated than simply extracting a value from a Hash. Also, attaching names to your bits of logic can help clarify what a chain of Enumerable method calls is trying … Read more
Hash-tables could not claim “amortized constant time insertion” if, for instance, the resizing was by a constant increment. In that case the cost of resizing (which grows with the size of the hash-table) would make the cost of one insertion linear in the total number of elements to insert. Because resizing becomes more and more … Read more
Example: def foo(regular, hash={}) puts “regular: #{regular}” puts “hash: #{hash}” puts “a: #{hash[:a]}” puts “b: #{hash[:b]}” end foo(“regular argument”, a: 12, :b => 13) I use hash={} to specify that the last argument is a hash, with default value of empty hash. Now, when I write: foo(“regular argument”, a: 12, :b => 13) It’s actually … Read more
There are couple of locations where this could be specified, i.e. a couple of things that are considered “The Ruby Language Specification”: the ISO Ruby Language Specification the RubySpec project the YARV testsuite The Ruby Programming Language book by matz and David Flanagan The ISO spec doesn’t say anything about Hash ordering: it was written … Read more
Switching to SHA512 will hardly make your website more secure. You should not write your own password hashing function. Instead, use an existing implementation. SHA256 and SHA512 are message digests, they were never meant to be password-hashing (or key-derivation) functions. (Although a message digest could be used a building block for a KDF, such as … Read more
From the quoted snippet in the question: [the Hash class] It is a stream that is both readable and writable. The written data is used to compute the hash. Once the writable side of the stream is ended, use the read() method to get the computed hash digest. So what you need to hash some … Read more
An MD5 or SHA1 hash in PHP returns a hexadecimal number, so all you need to do is convert bases. PHP has a function that can do this for you: $bignum = hexdec( md5(“test”) ); or $bignum = hexdec( sha1(“test”) ); PHP Manual for hexdec Since you want a limited size number, you could then … Read more
Here is a good explanation about hashing. For example you want to store the string “Rachel” you apply a hash function to that string to get a memory location. myHashFunction(key: “Rachel” value: “Rachel”) –> 10. The function may return 10 for the input “Rachel” so assuming you have an array of size 100 you store … Read more
It’s nothing special. As you can see if you examine the unbound __hash__ method of the function type: >>> def f(): pass … >>> type(f).__hash__ <slot wrapper ‘__hash__’ of ‘object’ objects> the of ‘object’ objects part means it just inherits the default identity-based __hash__ from object. Function == and hash work by identity. The difference … Read more
There is no way to send a password securely that the user can verify without SSL. Sure, you can write some JavaScript that will make a password secure for over-the-wire transmission through hashing or public-key-encryption. But how can the user be sure that the JavaScript itself has not been tampered with by a man-in-the-middle before … Read more