I have an array of shop objects which belong to city objects which belong to prefec开发者_运维问答ture objects
I\'m having tough time in understanding why the following works: my $array_reference; foreach $element (@{$array_reference}) {
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 autoviv
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:
Is there any way simpler than if hash.key?(\'a\') ha开发者_JAVA技巧sh[\'a\'][\'b\'] = \'c\' else hash[\'a\'] = {}
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.
if I have this SQL query: select substring(id for 2) as key, yw, count(*) from pref_money group by yw, key
The exists function can unexpectedly autovivify entries in hashes. What surprises me is that this behavior carries over to constants as well:
In order to implement auto-vivification of 开发者_如何学运维Ruby hash, one can employ the following class
This question already has answers here: What is the best way to implement nested dictionaries? 开发者_如何学编程
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