How to resolve the algorithm Visualize a tree step by step in the PHP programming language

Published on 12 May 2024 09:40 PM
#Php

How to resolve the algorithm Visualize a tree step by step in the PHP programming language

Table of Contents

Problem Statement

A tree structure   (i.e. a rooted, connected acyclic graph)   is often used in programming.
It's often helpful to visually examine such a structure. There are many ways to represent trees to a reader, such as: Write a program to produce a visual representation of some tree.
The content of the tree doesn't matter, nor does the output format, the only requirement being that the output is human friendly. Make do with the vague term "friendly" the best you can.

Let's start with the solution:

Step by Step solution about How to resolve the algorithm Visualize a tree step by step in the PHP programming language

The provided PHP code defines a function printTree() that visualizes a hierarchical data structure as a tree-like representation in the console. It takes an input array $tree and recursively prints its contents, creating a nested tree structure with proper indentation. The function supports multi-level hierarchical structures and provides visual cues to indicate the relationship between nodes.

Here's a detailed breakdown of how the code works:

  1. Function Signature:

    function printTree( array $tree , string $key = "." , string $stack = "" , $first = TRUE , $firstPadding = NULL )
    • $tree: The input hierarchical data structure represented as an array.
    • $key: The current key of the node being processed. Defaults to '.' (root node).
    • $stack: A string representing the current path to the node. Defaults to an empty string for the root node.
    • $first: A flag indicating whether the current node is the first child of its parent. Defaults to TRUE for the root node.
    • $firstPadding: A string representing the padding to be used for the first child of a parent. Defaults to '│ ' if not specified.

  2. Recursive Printing: The function recursively traverses the input array, printing each node's key and value. For arrays (sub-trees), it calls itself recursively to print their contents. For non-array values (leaf nodes), it prints the key and value separated by ' -> '.

  3. Indentation and Visual Cues: The function uses indentation and visual cues (such as '├──' and '└──') to indicate the hierarchical relationship between nodes. It uses the $stack parameter to accumulate the indentation for each level. For the first child of a parent, it uses $firstPadding for indentation.

  4. Root Node Handling: The root node is handled as a special case. It prints the root node key without indentation.

  5. Testing Function:

    • The code includes sample data in variables ($sample_array_1 to $sample_array_6).

    • It invokes the printTree() function on each sample array to demonstrate the tree visualization.

    • Sample arrays include arrays with different levels of nesting, including strings, numbers, and arrays.

    • For each sample array, it prints the hierarchical tree structure in the console, with proper indentation and visual cues to indicate the parent-child relationships.

Here's an example output for $sample_array_1:

.
├── 0 -> item_id: 6
│   ├── price: 2311.00
│   ├── qty: 12
│   └── discount: 0
├── 1 -> item_id: 7
│   ├── price: 1231.00
│   ├── qty: 1
│   └── discount: 12
└── 2 -> item_id: 8
   ├── price: 123896.00
   ├── qty: 0
   └── discount: 24

This output shows a tree-like structure with three child nodes under the root node. Each child node has its own key and value, and the indentation and visual cues make it clear which nodes belong to which parent.

Source code in the php programming language

<?php

function printTree( array $tree , string $key = "." , string $stack = "" , $first = TRUE , $firstPadding = NULL )
{
    if ( gettype($tree) == "array" )
    {
        if($firstPadding === NULL) $firstPadding = ( count($tree)>1 ) ? "│   " : "    " ;
        echo   $key . PHP_EOL ;
        foreach ($tree as $key => $value) {
            if ($key === array_key_last($tree)){
                echo (($first) ? "" : $firstPadding ) . $stack . "└── ";
                $padding = "    ";
                if($first) $firstPadding = "    ";
            }
            else {
                echo (($first) ? "" : $firstPadding ) . $stack . "├── ";
                $padding = "│   ";
            }
            if( is_array($value) )printTree( $value , $key ,   $stack . (($first) ? "" : $padding ) , FALSE , $firstPadding );
            else echo $key . " -> " . $value . PHP_EOL;
        }
    }
    else echo $tree . PHP_EOL;
}



// ---------------------------------------TESTING FUNCTION-------------------------------------


$sample_array_1 = 
[
    0 => [
        'item_id' => 6,
        'price' => "2311.00",
        'qty' => 12,
        'discount' => 0
    ],
    1 => [
        'item_id' => 7,
        'price' => "1231.00",
        'qty' => 1,
        'discount' => 12
    ],
    2 => [
        'item_id' => 8,
        'price' => "123896.00",
        'qty' => 0,
        'discount' => 24
    ]
];
$sample_array_2 = array(
    array(
         "name"=>"John",
        "lastname"=>"Doe",
        "country"=>"Japan",
        "nationality"=>"Japanese",
        "job"=>"web developer",
        "hobbies"=>array(
                "sports"=>"soccer",
                "others"=>array(
                        "freetime"=>"watching Tv"
                )
        )

    )
);
$sample_array_3 = [
    "root" => [
        "first_depth_node1" =>[
            "second_depth_node1",
            "second_depth_node2" => [
                "third_depth_node1" ,
                "third_depth_node2" ,
                "third_depth_node3" => [
                    "fourth_depth_node1",
                    "fourth_depth_node2",
                ]
                ],
            "second_depth_node3",
        ] ,
        "first_depth_node2" => [
            "second_depth_node4" => [ "third_depth_node3" => [1]]
        ]
        ]
];
$sample_array_4 = [];
$sample_array_5 = ["1"];
$sample_array_5 = ["1"];
$sample_array_6 = [
    "T",
    "Ta",
    "Tad",
    "Tada",
    "Tadav",
    "Tadavo",
    "Tadavom",
    "Tadavomn",
    "Tadavomni",
    "Tadavomnis",
    "TadavomnisT",
];


printTree($sample_array_1);
echo PHP_EOL . "------------------------------" . PHP_EOL;
printTree($sample_array_2);
echo PHP_EOL . "------------------------------" . PHP_EOL;
printTree($sample_array_3);
echo PHP_EOL . "------------------------------" . PHP_EOL;
printTree($sample_array_4);
echo PHP_EOL . "------------------------------" . PHP_EOL;
printTree($sample_array_5);
echo PHP_EOL . "------------------------------" . PHP_EOL;
printTree($sample_array_6);


?>

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