数组中出现次数最多的字符 php？

Question

请帮我做一个函数来解析以下数组和return一个包含最常出现的字符的数组，不区分大小写并排除特殊字符，计算输入

    $sentences = [
    0 => 'The tiger is the national animal of India',
    1 => 'The tiger is a large carnivorous mammal that roams the forests',
    2 => 'The tiger feeds on animals that also live in the forest',
    3 => 'The tiger does have a coat of orange with black stripes',
    4 => 'Tigers, regardless of their subspecies, are carnivorous animals',
    5 => 'The tiger is a protected species',
    ];

The code should output the following result: 

    Array
    (
    [0] => Array
    (
    [sentence] => The tiger is the national animal of India
    [character] => i
    [occurrences] => 6
    )

    [1] => Array
    (
    [sentence] => The tiger is a large carnivorous mammal that roams the forests
    [character] => a
    [occurrences] => 7
    )

    [2] => Array
    (
    [sentence] => The tiger feeds on animals that also live in the forest
    [character] => e
    [occurrences] => 7
    )

    [3] => Array
    (
    [sentence] => The tiger does have a coat of orange with black stripes
    [character] => e
    [occurrences] => 6
    )

    [4] => Array
    (
    [sentence] => Tigers, regardless of their subspecies, are carnivorous animals
    [character] => s
    [occurrences] => 8
    )

    [5] => Array
    (
    [sentence] => The tiger is a protected species
    [character] => e
    [occurrences] => 6
    )

    )

我试过了

foreach($sentences as $sentence) {
    $value = array_count_values($sentence);
}

请帮我做一个功能达到上述目的

Answer 1

您可以使用 array_map() to apply a function on each items. In this function, you could convert the string to lower case, split characters in an array (and array_filter() to remove spaces), in order to use array_count_values(). Then, you could sort the array using arsort() to keep keys association and get the most used character in the top. Finally, you could use array_keys() 和 reset() 来获取数组的第一个键和第一个值：

$sentences = [
  0 => 'The tiger is the national animal of India',
  1 => 'The tiger is a large carnivorous mammal that roams the forests',
  2 => 'The tiger feeds on animals that also live in the forest',
  3 => 'The tiger does have a coat of orange with black stripes',
  4 => 'Tigers, regardless of their subspecies, are carnivorous animals',
  5 => 'The tiger is a protected species',
];

$out = array_map(function($value) {
    $chars = array_filter(str_split(strtolower($value)),'trim');
    $vals = array_count_values($chars);
    arsort($vals);
    $keys = array_keys($vals);
    return [
        'sentence' => $value,
        'character' => reset($keys),
        'occurrences' => reset($vals),
    ];
}, $sentences);
print_r($out) ;

输出：

Array (
    [0] => Array (
            [sentence] => The tiger is the national animal of India
            [character] => i
            [occurrences] => 6
        )
    [1] => Array (
            [sentence] => The tiger is a large carnivorous mammal that roams the forests
            [character] => a
            [occurrences] => 7
        )
    [2] => Array (
            [sentence] => The tiger feeds on animals that also live in the forest
            [character] => e
            [occurrences] => 7
        )

    [3] => Array (
            [sentence] => The tiger does have a coat of orange with black stripes
            [character] => e
            [occurrences] => 6
        )

    [4] => Array (
            [sentence] => Tigers, regardless of their subspecies, are carnivorous animals
            [character] => s
            [occurrences] => 8
        )

    [5] => Array (
            [sentence] => The tiger is a protected species
            [character] => e
            [occurrences] => 6
        )
)

要删除特殊字符：

$chars = array_filter(str_split(strtolower($value)),function($val){
    return trim(preg_replace('~\W+~', '', $val));
});

Answer 2

我会使用 preg_match_all() 和一次匹配一个字母或数字的模式来提取字符数组，然后使用 array_count_values() 查找出现的次数，对数组进行排序按降序出现，然后提取第一个键和第一个值（表示出现次数最多的字母的字符和计数）。

代码：（演示：https://3v4l.org/7OZ5d）

$sentences = [
    0 => 'The tiger is the national animal of India',
    1 => 'The tiger is a large carnivorous mammal that roams the forests',
    2 => 'The tiger feeds on animals that also live in the forest',
    3 => 'The tiger does have a coat of orange with black stripes',
    4 => 'Tigers, regardless of their subspecies, are carnivorous animals',
    5 => 'The tiger is a protected species',
 ];

foreach  ($sentences as $sentence) {
    $alphanums = preg_match_all ('~[a-z\d]~', strtolower($sentence), $out) ? $out[0] : [];
    // or:  $alphanums = preg_split('~[^a-z\d]*~', strtolower($sentence), null, PREG_SPLIT_NO_EMPTY);
    $occurrences = array_count_values($alphanums);
    arsort($occurrences);
    $result[] = [
        "sentence" => $sentence,
        "character" => key($occurrences), 
        "occurrences" => current($occurrences)
    ];
}
var_export($result);

Answer 3

使用count_chars

$sentences = [
0 => 'The tiger is the national animal of India',
1 => 'The tiger is a large carnivorous mammal that roams the forests',
2 => 'The tiger feeds on animals that also live in the forest',
3 => 'The tiger does have a coat of orange with **a** black stripe',
4 => 'Tigers, regardless of their subspecies, are carnivorous animals',
5 => 'The tiger is a protected species',
];

我通过使用 count_chars() 到 $counts 来捕获出现次数，并通过使用 max() 获得最大出现次数。如果出现次数小于最大值，则从数组中删除 ASCII 代码（因为可能有多个字符具有相同的出现次数）。

通过调用 chr()

将剩余的 ASII 代码转换回字符

<?php
    foreach ($sentences as $sentence){
    $string = strtolower(preg_replace('/\s+/', '', $sentence));
    $counts = count_chars($string, 1);
    $max = max($counts);
    foreach ($counts as $key => $count) {
        if ($count < $max) {
            unset($counts[$key]);
        }
    }
    $characters = array_map(function($item){
           return chr($item);
        }, array_keys($counts));
    $result[] = [
        'sentence' => $sentence,
        'character' => implode(',', $characters),
        'occurrences' => $max
    ];
}

echo '<pre>', print_r($result) ,'<pre>';

输出：

    Array
(
    [0] => Array
        (
        [sentence] => The tiger is the national animal of India
        [character] => i
        [occurrences] => 6
    )

    [1] => Array
        (
            [sentence] => The tiger is a large carnivorous mammal that roams the forests
            [character] => a
            [occurrences] => 7
        )

    [2] => Array
        (
            [sentence] => The tiger feeds on animals that also live in the forest
            [character] => e
            [occurrences] => 7
        )

    [3] => Array
        (
            [sentence] => The tiger does have a coat of orange with a black stripe
            [character] => a,e **<== multiple characters**
            [occurrences] => 6
        )

    [4] => Array
        (
            [sentence] => Tigers, regardless of their subspecies, are carnivorous animals
            [character] => s
            [occurrences] => 8
        )

    [5] => Array
        (
            [sentence] => The tiger is a protected species
            [character] => e
            [occurrences] => 6
        )

)

只计算字母：

$string = strtolower(preg_replace('/[^A-Za-z]/', '', $sentence));

演示：http://sandbox.onlinephpfunctions.com/code/e2fb793031cd172507d8a464b1096b1b2bb73046

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