├── LICENSE.txt
├── README.md
├── composer.json
└── src
    ├── Statistics.php
    └── StatisticsError.php


/LICENSE.txt:
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 1 | Copyright (c) Oefenweb.nl <https://github.com/Oefenweb>
 2 | 
 3 | Permission is hereby granted, free of charge, to any person obtaining a copy
 4 | of this software and associated documentation files (the "Software"), to deal
 5 | in the Software without restriction, including without limitation the rights
 6 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 7 | copies of the Software, and to permit persons to whom the Software is furnished
 8 | to do so, subject to the following conditions:
 9 | 
10 | The above copyright notice and this permission notice shall be included in all
11 | copies or substantial portions of the Software.
12 | 
13 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
19 | THE SOFTWARE.
20 | 


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/README.md:
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 1 | # php-statistics
 2 | 
 3 | [![Build Status](https://travis-ci.org/Oefenweb/php-statistics.svg?branch=master)](https://travis-ci.org/Oefenweb/php-statistics)
 4 | [![PHP 7 ready](http://php7ready.timesplinter.ch/Oefenweb/php-statistics/badge.svg)](https://travis-ci.org/Oefenweb/php-statistics)
 5 | [![codecov](https://codecov.io/gh/Oefenweb/php-statistics/branch/master/graph/badge.svg)](https://codecov.io/gh/Oefenweb/php-statistics)
 6 | [![Packagist downloads](http://img.shields.io/packagist/dt/Oefenweb/statistics.svg)](https://packagist.org/packages/oefenweb/statistics)
 7 | [![Code Climate](https://codeclimate.com/github/Oefenweb/php-statistics/badges/gpa.svg)](https://codeclimate.com/github/Oefenweb/php-statistics)
 8 | [![Scrutinizer Code Quality](https://scrutinizer-ci.com/g/Oefenweb/php-statistics/badges/quality-score.png?b=master)](https://scrutinizer-ci.com/g/Oefenweb/php-statistics/?branch=master)
 9 | 
10 | Statistics library for PHP.
11 | 
12 | ## Requirements
13 | 
14 | * PHP 7.2.0 or greater.
15 | 
16 | ## Usage
17 | 
18 | ### Sum
19 | ```php
20 | use Oefenweb\Statistics\Statistics;
21 | 
22 | Statistics::sum([1, 2, 3]); // 6
23 | ```
24 | 
25 | ### Minimum
26 | ```php
27 | use Oefenweb\Statistics\Statistics;
28 | 
29 | Statistics::min([1, 2, 3]); // 1
30 | ```
31 | 
32 | ### Maximum
33 | ```php
34 | use Oefenweb\Statistics\Statistics;
35 | 
36 | Statistics::max([1, 2, 3]); // 3
37 | ```
38 | 
39 | ### Mean
40 | ```php
41 | use Oefenweb\Statistics\Statistics;
42 | 
43 | Statistics::mean([1, 2, 3]); // 2
44 | ```
45 | 
46 | ### Frequency
47 | ```php
48 | use Oefenweb\Statistics\Statistics;
49 | 
50 | Statistics::frequency([1, 2, 3, 3, 3]); // [1 => 1, 2 => 1, 3 => 3]
51 | ```
52 | 
53 | ### Mode
54 | ```php
55 | use Oefenweb\Statistics\Statistics;
56 | 
57 | Statistics::mode([1, 2, 2, 3]); // 2
58 | ```
59 | 
60 | ### Variance (sample and population)
61 | ```php
62 | use Oefenweb\Statistics\Statistics;
63 | 
64 | Statistics::variance([1, 2, 3]); // 1
65 | Statistics::variance([1, 2, 3], false); // 0.66666666666667
66 | ```
67 | 
68 | ### Standard deviation (sample and population)
69 | ```php
70 | use Oefenweb\Statistics\Statistics;
71 | 
72 | Statistics::standardDeviation([1, 2, 3]); // 1.0
73 | Statistics::standardDeviation([1, 2, 3], false); // 0.81649658092773
74 | ```
75 | 
76 | ### Range
77 | ```php
78 | use Oefenweb\Statistics\Statistics;
79 | 
80 | Statistics::range([4, 6, 10, 15, 18]); // 14
81 | ```
82 | 


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/composer.json:
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 1 | {
 2 | 	"name": "oefenweb/statistics",
 3 | 	"description": "Statistics library for PHP",
 4 | 	"type": "library",
 5 | 	"keywords": [
 6 | 		"statistics"
 7 | 	],
 8 | 	"homepage": "http://github.com/Oefenweb/php-statistics",
 9 | 	"license": "MIT",
10 | 	"authors": [
11 | 		{
12 | 			"name": "Oefenweb.nl BV team",
13 | 			"homepage": "https://github.com/Oefenweb/php-statistics/contributors"
14 | 		}
15 | 	],
16 | 	"require": {
17 | 		"php": ">=7.0.0"
18 | 	},
19 | 	"support": {
20 | 		"issues": "https://github.com/Oefenweb/php-statistics/issues",
21 | 		"source": "https://github.com/Oefenweb/php-statistics"
22 | 	},
23 | 	"autoload": {
24 | 		"psr-4": {
25 | 			"Oefenweb\\Statistics\\": "src"
26 | 		}
27 | 	},
28 | 	"autoload-dev": {
29 | 		"psr-4": {
30 | 			"Oefenweb\\Statistics\\Test\\": "tests"
31 | 		}
32 | 	}
33 | }
34 | 


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/src/Statistics.php:
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  1 | <?php
  2 | namespace Oefenweb\Statistics;
  3 | 
  4 | use Oefenweb\Statistics\StatisticsError;
  5 | 
  6 | /**
  7 |  * Statistics Library.
  8 |  *
  9 |  */
 10 | class Statistics
 11 | {
 12 | 
 13 |     /**
 14 |      * Calculates the sum for a given set of values.
 15 |      *
 16 |      * @param array $values The input values
 17 |      * @return float|int The sum of values as an integer or float
 18 |      */
 19 |     public static function sum(array $values)
 20 |     {
 21 |         return array_sum($values);
 22 |     }
 23 | 
 24 |     /**
 25 |      * Calculates the minimum for a given set of values.
 26 |      *
 27 |      * @param array $values The input values
 28 |      * @return float|int The minimum of values as an integer or float
 29 |      */
 30 |     public static function min(array $values)
 31 |     {
 32 |         return min($values);
 33 |     }
 34 | 
 35 |     /**
 36 |      * Calculates the maximum for a given set of values.
 37 |      *
 38 |      * @param array $values The input values
 39 |      * @return float|int The maximum of values as an integer or float
 40 |      */
 41 |     public static function max(array $values)
 42 |     {
 43 |         return max($values);
 44 |     }
 45 | 
 46 |     /**
 47 |      * Calculates the mean for a given set of values.
 48 |      *
 49 |      * @param array $values The input values
 50 |      * @return float|int The mean of values as an integer or float
 51 |      */
 52 |     public static function mean(array $values)
 53 |     {
 54 |         $numberOfValues = count($values);
 55 | 
 56 |         if ($numberOfValues < 1) {
 57 |             throw new StatisticsError('The mean requires at least one data point.');
 58 |         }
 59 | 
 60 |         return self::sum($values) / $numberOfValues;
 61 |     }
 62 | 
 63 |     /**
 64 |      * Calculates the frequency table for a given set of values.
 65 |      *
 66 |      * @param array $values The input values
 67 |      * @return array The frequency table
 68 |      */
 69 |     public static function frequency(array $values): array
 70 |     {
 71 |         $frequency = [];
 72 |         foreach ($values as $value) {
 73 |             // Floats cannot be indices
 74 |             if (is_float($value)) {
 75 |                 $value = strval($value);
 76 |             }
 77 | 
 78 |             if (!isset($frequency[$value])) {
 79 |                 $frequency[$value] = 1;
 80 |             } else {
 81 |                 $frequency[$value] += 1;
 82 |             }
 83 |         }
 84 | 
 85 |         asort($frequency);
 86 | 
 87 |         return $frequency;
 88 |     }
 89 | 
 90 |     /**
 91 |      * Calculates the mode for a given set of values.
 92 |      *
 93 |      * @param array $values The input values
 94 |      * @return float|int The mode of values as an integer or float
 95 |      * @throws \Oefenweb\Statistics\StatisticsError
 96 |      */
 97 |     public static function mode(array $values)
 98 |     {
 99 |         $frequency = self::frequency($values);
100 | 
101 |         if (count($frequency) === 1) {
102 |             return key($frequency);
103 |         }
104 | 
105 |         $lastTwo = array_slice($frequency, -2, 2, true);
106 |         $firstFrequency = current($lastTwo);
107 |         $lastFrequency = next($lastTwo);
108 | 
109 |         if ($firstFrequency !== $lastFrequency) {
110 |             return key($lastTwo);
111 |         }
112 | 
113 |         throw new StatisticsError('There is not exactly one most common value.');
114 |     }
115 | 
116 |     /**
117 |      * Calculates the square of value - mean.
118 |      *
119 |      * @param float|int $value The input value
120 |      * @param float|int $mean The mean
121 |      * @return float|int The square of value - mean
122 |      */
123 |     protected static function squaredDifference($value, $mean)
124 |     {
125 |         return pow($value - $mean, 2);
126 |     }
127 | 
128 |     /**
129 |      * Calculates the variance for a given set of values.
130 |      *
131 |      * @param array $values The input values
132 |      * @param bool $sample Whether or not to compensate for small samples (n - 1), defaults to true
133 |      * @return float|int The variance of values as an integer or float
134 |      * @throws \Oefenweb\Statistics\StatisticsError
135 |      */
136 |     public static function variance(array $values, bool $sample = true)
137 |     {
138 |         $numberOfValues = count($values);
139 | 
140 |         if ($numberOfValues < 2) {
141 |             throw new StatisticsError('The variance requires at least two data points.');
142 |         }
143 | 
144 |         $mean = self::mean($values);
145 | 
146 |         $squaredDifferences = [];
147 |         foreach ($values as $value) {
148 |             $squaredDifferences[] = self::squaredDifference($value, $mean);
149 |         }
150 |         $sumOfSquaredDifferences = self::sum($squaredDifferences);
151 | 
152 |         if ($sample) {
153 |             $variance = $sumOfSquaredDifferences / ($numberOfValues - 1);
154 |         } else {
155 |             $variance = $sumOfSquaredDifferences / $numberOfValues;
156 |         }
157 | 
158 |         return $variance;
159 |     }
160 | 
161 |     /**
162 |      * Calculates the standard deviation for a given set of values.
163 |      *
164 |      * @param array $values The input values
165 |      * @param bool $sample Whether or not to compensate for small samples (n - 1), defaults to true
166 |      * @return float|int The standard deviation of values as an integer or float
167 |      */
168 |     public static function standardDeviation(array $values, bool $sample = true)
169 |     {
170 |         return sqrt(self::variance($values, $sample));
171 |     }
172 | 
173 |     /**
174 |      * Calculates the range for a given set of values.
175 |      *
176 |      * @param array $values The input values
177 |      * @return float|int The range of values as an integer or float
178 |      */
179 |     public static function range(array $values)
180 |     {
181 |         return self::max($values) - self::min($values);
182 |     }
183 | }
184 | 


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/src/StatisticsError.php:
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 1 | <?php
 2 | namespace Oefenweb\Statistics;
 3 | 
 4 | use Exception;
 5 | 
 6 | /**
 7 |  * Statistics Error.
 8 |  *
 9 |  */
10 | class StatisticsError extends Exception
11 | {
12 | }
13 | 


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