autovivification

Update: My original intention for this question was to determine if PHP actually has this feature. This has been lost in the answers' focus on the scalar issue. Please see this new question instead: "Does PHP have autovivification?" This question is left here for reference. According to Wikipedia , PHP doesn't have autovivification, yet this code works: $test['a']['b'] = 1; $test['a']['c'] = 1; $test['b']['b'] = 1; $test['b']['c'] = 1; var_dump($test); Output: array 'a' => array 'b' => int 1 'c' => int 1 'b' => array 'b' => int 1 'c' => int 1 I found that this code works too: $test['a'][4] = 1

Searching PHP.net for autovivification gives no results. At the time of writing, Wikipedia claims that only Perl has it. There are no clearly definitive results when searching Google for "php autovivification". This PHP code runs fine: $test['a'][4][6]['b'] = "hello world"; var_dump($test); array 'a' => array 4 => array 'b' => array ... Can anyone provide a canonical answer (preferably with references) that PHP does have this feature, and any details such as the version it was introduced in, quirks, shortcuts etc? Yes, PHP does have autovivification (and has had it for a long time), although

So I'm writing a class that extends a dictionary which right now uses a method "dictify" to transform itself into a dict. What I would like to do instead though is change it so that calling dict() on the object results in the same behavior, but I don't know which method to override. Is this not possible, or I am I missing something totally obvious? (And yes, I know the code below doesn't work but I hope it illustrates what I'm trying to do.) from collections import defaultdict class RecursiveDict(defaultdict): ''' A recursive default dict. >>> a = RecursiveDict() >>> a[1][2][3] = 4 >>> a

In python 2.7, I have a bunch of files stored as the following object: class AutoVivification(dict): """Implementation of perl's autovivification feature.""" def __getitem__(self, item): try: return dict.__getitem__(self, item) except KeyError: value = self[item] = type(self)() return value This is from What is the best way to implement nested dictionaries? . I have them pickled and can load them just fine. But in python 3.6, it gives me the following error when trying to load the same file. Traceback (most recent call last): File "C:\Program Files\JetBrains\PyCharm Community Edition 2018.3.1

i am trying to make an inversed document index, therefore i need to know from all unique words in a collection in which doc they occur and how often. i have used this answer in order two create a nested dictionary. The provided solution works fine, with one problem though. First i open the file and make a list of unique words. These unique words i than want to compare with the original file. When there is a match, the frequency counter should be updated and its value be stored in the two dimensional array. output should eventually look like this: word1, {doc1 : freq}, {doc2 : freq} <br> word2,

I would like to expand on the autovivification example given in a previous answer from nosklo to allow dictionary access by tuple. nosklo's solution looks like this: class AutoVivification(dict): """Implementation of perl's autovivification feature.""" def __getitem__(self, item): try: return dict.__getitem__(self, item) except KeyError: value = self[item] = type(self)() return value Testing: a = AutoVivification() a[1][2][3] = 4 a[1][3][3] = 5 a[1][2]['test'] = 6 print a Output: {1: {2: {'test': 6, 3: 4}, 3: {3: 5}}} I have a case where I want to set a node given some arbitrary tuple of

Is there anyway, either natively or through a library, to use autovivification on Javascript objects? IE, assuming foo is an object with no properties, being able to just do foo.bar.baz = 5 rather than needing foo.bar = {}; foo.bar.baz = 5 . You can't do it exactly with the syntax you want. But as usual, in JS you can write your own function: function set (obj,keys,val) { for (var i=0;i<keys.length;i++) { var k = keys[i]; if (typeof obj[k] == 'undefined') { obj[k] = {}; } obj = obj[k]; } obj = val; } so now you can do this: // as per you example: set(foo,['bar','baz'],5); without worrying if