PHP Arrays

00-readme.md

Some examples.

10-arrays.php

<?php
$list = array( 'orange', 'apple', 'pear' );

11-arrays.php

<?php
$list = [ 'orange', 'apple', 'pear' ];

12-associative-array.php

<?php
$ages_in_nelio = array(
  'toni'  => 34,
  'david' => 33,
  'ruth'  => 0, // unknown value
);

20-filter.php

<?php
add_filter( 'body_class', 'multisite_body_classes' );

function multisite_body_classes( $classes ) {
  $id = get_current_blog_id();
  $slug = strtolower( str_replace( ' ', '-', trim( get_bloginfo( 'name' ) ) ) );
  $classes[] = $slug;
  $classes[] = 'site-id-' . $id;
  return $classes;
}

21-filter-anonymous.php

<?php
add_filter( 'body_class', function( $classes ) {
  $id = get_current_blog_id();
  $slug = strtolower( str_replace( ' ', '-', trim( get_bloginfo( 'name' ) ) ) );
  $classes[] = $slug;
  $classes[] = 'site-id-' . $id;
  return $classes;
} );

22-remove-filter.php

<?php
remove_filter( 'body_class', 'multisite_body_classes' );

30-filter-old.php

<?php
function filter_expensive_products( $products, $min_price ) {
  $result = array();
  foreach ( $products as $product ) {
    if ( $min_price < $product['price'] ) {
      array_push( $reuslt, $product );
    }
  }
  return $result;
}

31-filter-new.php

<?php
function filter_expensive_products( $products, $min_price ) {
  return array_values( array_filter(
    $products,
    function( $product ) use ( $min_price ) {
      return $min_price < $product['price'];
    }
  ) );
}

32-filter-associative.php

<?php
$people = array(
  'john'     => 29,
  'peter'    => 38,
  'stephany' => 34,
  'mark'     => 28,
);

$people_in_their_twenties = array_filter( $people, function( $age ) {
  return 20 <= $age && $age < 30;
} );

// Returns:
// array(
//   'john' => 29,
//   'mark' => 28,
// )

33-filter-non-associative.php

<?php
$products = array(
  [ 'name' => 'X', 'price' => 20 ],
  [ 'name' => 'Y', 'price' => 50 ],
  [ 'name' => 'Z', 'price' => 12 ],
  [ 'name' => 'W', 'price' => 31 ],
);

$cheap_products = array_filter( $products, function( $product ) {
  return $product['price'] <= 20;
} );

// Returns:
// array(
//   0 => [ 'name' => 'X', 'price' => 20 ],
//   2 => [ 'name' => 'Z', 'price' => 12 ],
// )

34-filter-non-assoc-with-values.php

<?php
$products = array(
  [ 'name' => 'X', 'price' => 20 ],
  [ 'name' => 'Y', 'price' => 50 ],
  [ 'name' => 'Z', 'price' => 12 ],
  [ 'name' => 'W', 'price' => 31 ],
);

$cheap_products = array_values(
  array_filter( $products, function( $product ) {
    return $product['price'] <= 20;
  } )
);

// Returns:
// array(
//   0 => [ 'name' => 'X', 'price' => 20 ],
//   1 => [ 'name' => 'Z', 'price' => 12 ],
// )

40-search-old.php

<?php
function search_product( $products, $name ) {
  $item = false;
  foreach ( $products as $product ) {
    if ( ! $item && $product['name'] === $name ) {
      $item = $product;
    }//end if
  }
  return $item;
}

41-search-new.php

<?php
function search_product( $products, $name ) {
  $matching_items = array_values( array_filter(
    $products,
    function( $product ) use ( $name ) {
      return $product['name'] === $name;
    }
  ) );
  return $matching_items[0];
}

50-map-old.php

<?php
function apply_vat( $products ) {
  $result = array();
  foreach ( $prices as $price ) {
    array_push( $result, $price * 1.21 );
  }
  return $result;
}

51-map-new.php

<?php
function apply_vat( $prices ) {
  return array_map( function( $price ) {
    return $price * 1.21;
  }, $prices );
}

60-reduce-old.php

<?php
function compute_total_price( $products ) {
  $total_price = 0;
  foreach ( $products as $product ) {
    $total_price += $product['price']
  }
  return $total_price;
}

61-reduce-new.php

<?php
function compute_total_price( $products ) {
  return array_reduce(
    $products,
    function( $total_price, $product ) {
      return $total_price + $product['price'];
    },
    0
  );
}

70-diff.php

<?php
$fruits = [ 'orange', 'pear', 'pineapple', 'apple', 'strawberry' ];
$fruits_i_like = [ 'orange', 'apple' ];

$fruits_i_dont_like = array_diff( $fruits, $fruits_i_like );

// Result:
// [ 'pear', 'pineapple', 'strawberry' ];

71-unique.php

<?php
$items = [ 'apple', 'orange', 'pear', 'pear', 'apple', 'apple' ];
$items = array_unique( $items );

// Result:
// [ 'apple', 'orange', 'pear' ]

72-in-array.php

<?php
$fruits = [ 'orange', 'pineapple', 'apple', 'strawberry' ];

$has_apple = in_array( 'apple', $fruits );
// Result: true

$has_pear = in_array( 'pear', $fruits );
// Result: false