CODEWITHSUNDEEP
phpperlhash
user3872809
user3872809

Reputation: 3

How to convert perl hash of hash of hash to php

I am currently looking a rewriting some perl cgi scripts into php, mainly in order so I can learn php. Everything is going well, except I can't get my head round how to convert a perl hash of hash of hash into a php array. Take this scenario (not real, but the idea is the same) I have 5 network nodes called A,B,C,D,E. Each node is actually a stack of 3 switches called TOP, MIDDLE, BOTTOM Each switch has 10 interfaces called 1 to 10.

I have a script that polls round every interface and record the input bytes in a database like this:-

node   switch   interface  bytes
 A      TOP       1         999
 B     MIDDLE     1         999
 A     MIDDLE     2         999

etc

I can read the database in php, but then I come unstuck. In perl I just read the data and store it in a hash of hashes by looping though the query of the database

`While $ref fetchrow_hashref() {
    $hash{$ref{'NODE'}}{$ref{'Switch'}}{$ref{'Interface'}=$ref{'Bytes'}
}`

So now I can access any value in my cgi code using the names $hash{A}{Top}{1} would return 999

But when I try and do something similar in php with associative array of arrays, it go wrong. I've used

$hash[]=[$ref["NODE"}=>
    [$ref["Switch"]=>
        [$ref["Interface"]=>
            $ref["Bytes"]
        ]
    ]
];

A var_dump of the hash looks correct, but I don't appear to be able to print a value out of the array using print $hash[A][TOP][1];

Please can I have pointers to my mistakes

Upvotes: 0

Views: 232

Answers (1)

VolkerK
VolkerK

Reputation: 96159

That would be 

while( $ref=somefetchingfunction_or_method() ) {
    $hash[$ref['NODE']][$ref['Switch']][$ref['Interface']]=$ref['Bytes'];

(i.e. just replacing all { by [, } by ] and fixing the missing last ].)

edit: sscce:

<?php
$hash = [];
foreach( gen_fetch() as $ref ) {
    $hash[$ref['NODE']][$ref['Switch']][$ref['Interface']]=$ref['Bytes'];
}
echo $hash['A']['TOP'][1];

// generator requires php version >= 5.5, see http://php.net/language.generators.overview
function gen_fetch() {
    $keys = ['NODE','Switch','Interface','Bytes'];
    foreach( [['A','TOP',1,997],['B','MIDDLE',1,998],['A','MIDDLE',2,999]] as $r) {
        yield array_combine($keys,$r);
    }
}

prints 997.

Upvotes: 1

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