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• Kumite (ko͞omiˌtā) is the practice of taking techniques learned from Kata and applying them through the act of freestyle sparring.

You can create a new kumite by providing some initial code and optionally some test cases. From there other warriors can spar with you, by enhancing, refactoring and translating your code. There is no limit to how many warriors you can spar with.

A great use for kumite is to begin an idea for a kata as one. You can collaborate with other code warriors until you have it right, then you can convert it to a kata.

# Kata in PHP #13 - Genetic Algorithm Series - #5 Roulette wheel selection

## Kata

Genetic Algorithm Series - #5 Roulette wheel selection (6kyu)

## Side Note

Guess what my next "Kata in PHP" Kumite might be about ;)

``````function select(\$population, \$fitnesses) {
\$sum_fitnesses = array_reduce(\$fitnesses, function (\$sum, \$fitness) {
return \$sum + \$fitness;
}, 0);
\$i = 0;
\$k = 0;
while (true) {
\$rand = lcg_value();
if (\$rand < \$fitnesses[\$i % count(\$fitnesses)] / \$sum_fitnesses && \$k >= 33) {
return \$population[\$i % count(\$population)];
} else if (\$rand < \$fitnesses[\$i % count(\$fitnesses)] / \$sum_fitnesses) {
\$k++;
}
\$i++;
}
}

\$test->describe('select(\$population, \$fitnesses)', function () {
global \$test;
\$test->it("should return the correct proportion for each 'chromosome' according to their relative fitnesses", function () {
global \$test;
\$population = [1, 2, 3, 4];
\$fitnesses = [0.01, 0.01, 0.01, 0.01];
\$selection = [];
for (\$i = 0; \$i < 1000; \$i++) {
array_push(\$selection, select(\$population, \$fitnesses));
}
\$ones = count(array_filter(\$selection, function (\$c) {
return \$c === 1;
}));
\$twos = count(array_filter(\$selection, function (\$c) {
return \$c === 2;
}));
\$threes = count(array_filter(\$selection, function (\$c) {
return \$c === 3;
}));
\$fours = count(array_filter(\$selection, function (\$c) {
return \$c === 4;
}));
\$test->expect(\$ones >= 200 && \$ones <= 300, "Your probability is more than 5% off in 1000 runs");
\$test->expect(\$twos >= 200 && \$twos <= 300, "Your probability is more than 5% off in 1000 runs");
\$test->expect(\$threes >= 200 && \$threes <= 300, "Your probability is more than 5% off in 1000 runs");
\$test->expect(\$fours >= 200 && \$fours <= 300, "Your probability is more than 5% off in 1000 runs");
\$population = [1, 2, 3];
\$fitnesses = [0.5, 0.5, 1];
\$selection = [];
for (\$i = 0; \$i < 1000; \$i++) {
array_push(\$selection, select(\$population, \$fitnesses));
}
\$ones = count(array_filter(\$selection, function (\$c) {
return \$c === 1;
}));
\$twos = count(array_filter(\$selection, function (\$c) {
return \$c === 2;
}));
\$threes = count(array_filter(\$selection, function (\$c) {
return \$c === 3;
}));
\$test->expect(\$ones >= 200 && \$ones <= 300, "Your probability is more than 5% off in 1000 runs");
\$test->expect(\$twos >= 200 && \$twos <= 300, "Your probability is more than 5% off in 1000 runs");
\$test->expect(\$threes >= 450 && \$threes <= 550, "Your probability is more than 5% off in 1000 runs");
\$population = [1, 2, 3];
\$fitnesses = [0.0001, 0.0001, 0.0002];
\$selection = [];
for (\$i = 0; \$i < 1000; \$i++) {
array_push(\$selection, select(\$population, \$fitnesses));
}
\$ones = count(array_filter(\$selection, function (\$c) {
return \$c === 1;
}));
\$twos = count(array_filter(\$selection, function (\$c) {
return \$c === 2;
}));
\$threes = count(array_filter(\$selection, function (\$c) {
return \$c === 3;
}));
\$test->expect(\$ones >= 200 && \$ones <= 300, "Your probability is more than 5% off in 1000 runs");
\$test->expect(\$twos >= 200 && \$twos <= 300, "Your probability is more than 5% off in 1000 runs");
\$test->expect(\$threes >= 450 && \$threes <= 550, "Your probability is more than 5% off in 1000 runs");
\$population = [1, 2, 3, 4];
\$fitnesses = [0.8, 0.6, 0.4, 0.2];
\$selection = [];
for (\$i = 0; \$i < 1000; \$i++) {
array_push(\$selection, select(\$population, \$fitnesses));
}
\$ones = count(array_filter(\$selection, function (\$c) {
return \$c === 1;
}));
\$twos = count(array_filter(\$selection, function (\$c) {
return \$c === 2;
}));
\$threes = count(array_filter(\$selection, function (\$c) {
return \$c === 3;
}));
\$fours = count(array_filter(\$selection, function (\$c) {
return \$c === 4;
}));
\$test->expect(\$ones >= 350 && \$ones <= 450);
\$test->expect(\$twos >= 250 && \$twos <= 350);
\$test->expect(\$threes >= 150 && \$threes <= 250);
\$test->expect(\$fours >= 50 && \$fours <= 150);
\$population = [1, 2, 3, 4, 5];
\$fitnesses = [0.1, 0.4, 0, 0.3, 0.2];
\$selection = [];
for (\$i = 0; \$i < 1000; \$i++) {
array_push(\$selection, select(\$population, \$fitnesses));
}
\$ones = count(array_filter(\$selection, function (\$c) {
return \$c === 1;
}));
\$twos = count(array_filter(\$selection, function (\$c) {
return \$c === 2;
}));
\$threes = count(array_filter(\$selection, function (\$c) {
return \$c === 3;
}));
\$fours = count(array_filter(\$selection, function (\$c) {
return \$c === 4;
}));
\$fives = count(array_filter(\$selection, function (\$c) {
return \$c === 5;
}));
\$test->expect(\$ones >= 50 && \$ones <= 150);
\$test->expect(\$twos >= 350 && \$twos <= 450);
\$test->expect(\$threes === 0, "For a chromosome of fitness 0, it should never be chosen");
\$test->expect(\$fours >= 250 && \$fours <= 350);
\$test->expect(\$fives >= 150 && \$fives <= 250);
});
});``````

# Kata in PHP #12 - Genetic Algorithm Series - #4 Get population and fitnesses

## Kata

Genetic Algorithm Series - #4 Get population and fitnesses (Beta)

``````function map_population_fit(\$population, \$fitness) {
return array_map(function (\$chromosome, \$formula) {
return ["chromosome" => \$chromosome, "fitness" => \$formula(\$chromosome)];
}, \$population, array_fill(0, count(\$population), \$fitness));
}

\$test->describe('map_population_fit(\$population, \$fitness)', function () {
global \$test;
\$test->it("should return an array of the correct format and with the correct entries for the given population", function () {
global \$test;
\$population = ['10100111', '11011100',
'01101000', '01100111', '01000010', '10001001', '10111100', '11111000', '11001100',
'00001011', '01011011', '01000111', '11010101', '00101101', '00100111', '00000111',
'00101000', '00101011', '01011011', '10100001', '00111000', '00010110', '00101100',
'11111110', '10101001', '11101001', '00011001', '10100011', '11000001', '11010101',
'11000110', '01111000', '11011000', '00111010', '11110100', '00100111', '10001101',
'11000100', '01110010', '10011111', '10110101', '11001100', '00110111', '00000100',
'10010010', '00011000', '10111010', '10001000', '00010011', '01001011', '00100010',
'01111000', '01110111', '11101011', '00001010', '00000000', '01100011', '00011111',
'10000001', '01100010', '11011100', '10001100', '01110010', '11011011', '00000111',
'10100100', '00101101', '00001101', '10010110', '10101110', '00111010', '00011001',
'11000110', '01010101', '00101000', '00000110', '11001000', '11000110', '01010100',
'01011010', '00101101', '00011001', '00010101', '10101110', '01100010', '01110101',
'01111011', '00111000', '11101110', '00110100', '11100100', '01011101', '10000110',
'11111101', '11000001', '11000111', '11000111', '01011000', '10011011', '10110101'];
function fitness(\$c) {
\$ideal = '10011001';
\$r = 0;
for (\$i = 0; \$i < strlen(\$c); \$i++) {
if (str_split(\$c)[\$i] === str_split(\$ideal)[\$i]) \$r++;
}
return \$r / strlen(\$ideal);
}
\$actual = map_population_fit(\$population, 'fitness');
for (\$i = 0; \$i < count(\$population); \$i++) {
\$test->assert_similar(\$actual[\$i], ["chromosome" => \$population[\$i], "fitness" => fitness(\$population[\$i])]);
}
});
});``````

# Kata in PHP #11 - Genetic Algorithm Series - #3 Crossover

## Kata

Genetic Algorithm Series - #3 Crossover (7kyu)

``````function crossover(\$chromosome1, \$chromosome2, \$index) {
\$new_chromosome1 = [];
for (\$i = 0; \$i < \$index; \$i++) {
array_push(\$new_chromosome1, str_split(\$chromosome1)[\$i]);
}
for (\$i = \$index; \$i < strlen(\$chromosome1); \$i++) {
array_push(\$new_chromosome1, str_split(\$chromosome2)[\$i]);
}
\$new_chromosome2 = [];
for (\$i = 0; \$i < \$index; \$i++) {
array_push(\$new_chromosome2, str_split(\$chromosome2)[\$i]);
}
for (\$i = \$index; \$i < strlen(\$chromosome2); \$i++) {
array_push(\$new_chromosome2, str_split(\$chromosome1)[\$i]);
}
return [implode(\$new_chromosome1), implode(\$new_chromosome2)];
}

\$test->describe("The chromosome crossover function", function () {
global \$test;
\$test->it("should work for the example in the description", function () {
global \$test;
\$test->assert_similar(crossover('111000', '000110', 3), ['111110', '000000']);
});
\$test->it("should work for basic tests", function () {
global \$test;
\$test->assert_similar(crossover('', '', 0), ['', '']);
\$test->assert_similar(crossover('01', '10', 1), ['00', '11']);
\$test->assert_similar(crossover('00000000', '11111111', 0), ['11111111', '00000000']);
\$test->assert_similar(crossover('00000000', '11111111', 7), ['00000001', '11111110']);
});
\$test->it("should work for more fixed tests", function () {
global \$test;
\$test->assert_similar(crossover('0000', '1111', 0), ['1111', '0000']);
\$test->assert_similar(crossover('0000', '1111', 1), ['0111', '1000']);
\$test->assert_similar(crossover('0000', '1111', 2), ['0011', '1100']);
\$test->assert_similar(crossover('0000', '1111', 3), ['0001', '1110']);
\$test->assert_similar(crossover('0000', '1111', 4), ['0000', '1111']);
\$test->assert_similar(crossover('0010011110', '1110010100', 3), ['0010010100', '1110011110']);
\$test->assert_similar(crossover('0010011110', '1110010100', 7), ['0010011100', '1110010110']);
});
});``````

# Kata in PHP #10 - Genetic Algorithm Series - #2 Mutation

## Kata

Genetic Algorithm Series - #2 Mutation (7kyu)

``````function mutate(\$chromosome, \$probability) {
return implode(array_map(function (\$d, \$p) {
return lcg_value() < \$p ? (\$d === '0' ? '1' : '0') : \$d;
}, str_split(\$chromosome), array_fill(0, strlen(\$chromosome), \$probability)));
}

\$test->describe("The chromosome mutating function", function () {
global \$test;
\$test->it("should convert all '0's to '1's and vice versa when the mutation probability is 1 (100%)", function () {
global \$test;
\$test->assert_equals(mutate('0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000', 1), '1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111');
\$test->assert_equals(mutate('1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111', 1), '0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000');
});
\$test->it("should not mutate the chromosome at all when the probability is 0", function () {
global \$test;
\$test->assert_equals(mutate('0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000', 0), '0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000');
\$test->assert_equals(mutate('1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111', 0), '1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111');
});
\$test->it('should mutate about 50% of the chromosome when the mutation probability is 0.5 (50%)', function () {
global \$test;
\$all_zeroes = '0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000';
\$all_ones = '1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111';
\$mutated = mutate(\$all_zeroes, 0.5);
\$test->expect(count(array_filter(str_split(\$mutated), function (\$d) {return \$d === '0';})) >= 35 && count(array_filter(str_split(\$mutated), function (\$d) {return \$d === '0';})) <= 65);
\$test->expect(count(array_filter(str_split(\$mutated), function (\$d) {return \$d === '1';})) >= 35 && count(array_filter(str_split(\$mutated), function (\$d) {return \$d === '1';})) <= 65);
\$mutated = mutate(\$all_ones, 0.5);
\$test->expect(count(array_filter(str_split(\$mutated), function (\$d) {return \$d === '0';})) >= 35 && count(array_filter(str_split(\$mutated), function (\$d) {return \$d === '0';})) <= 65);
\$test->expect(count(array_filter(str_split(\$mutated), function (\$d) {return \$d === '1';})) >= 35 && count(array_filter(str_split(\$mutated), function (\$d) {return \$d === '1';})) <= 65);
});
\$test->it("should work properly for random mutation probabilities", function () {
global \$test;
for (\$i = 0; \$i < 5; \$i++) {
echo "Testing a mutation probability of " . (\$p = lcg_value()) . "<br />";
echo "Your mutated chromosome: " . (\$mutated = mutate('0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000', \$p)) . "<br />";
\$test->expect(preg_match('/0/', \$mutated));
\$test->expect(preg_match('/1/', \$mutated));
}
});
});``````

# Kata in PHP #9 - Genetic Algorithm Series - #1 Generate

## Kata

Genetic Algorithm Series - #1 Generate (7kyu)

``````function generate(\$length) {
\$chromosome = "";
for (\$i = 0; \$i < \$length; \$i++) {
\$chromosome .= round(lcg_value());
}
return \$chromosome;
}

\$test->describe("The chromosome generator", function () {
global \$test;
\$test->it("should respect the given length", function () {
global \$test;
\$test->assert_equals(strlen(generate(0)), 0);
\$test->assert_equals(strlen(generate(1)), 1);
\$test->assert_equals(strlen(generate(8)), 8);
\$test->assert_equals(strlen(generate(16)), 16);
\$test->assert_equals(strlen(generate(32)), 32);
\$test->assert_equals(strlen(generate(64)), 64);
\$test->assert_equals(strlen(generate(256)), 256);
});
\$test->it("should probably produce chromosomes with at least 1 '1' and at least 1 '0' for length 50", function () {
global \$test;
\$chromosome = generate(50);
\$test->expect(preg_match('/0/', \$chromosome), "Your chromosome did not contain a single '0'");
\$test->expect(preg_match('/1/', \$chromosome), "Your chromosome did not contain a single '1'");
});
\$test->it("should probably return all possible chromosomes of length 5 when run 20000 times", function () {
global \$test;
\$chromosomes = [];
for (\$i = 0; \$i < 20000; \$i++) {
array_push(\$chromosomes, generate(5));
}
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '00000';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '00001';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '00010';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '00011';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '00100';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '00101';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '00110';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '00111';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '01000';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '01001';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '01010';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '01011';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '01100';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '01101';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '01110';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '01111';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '10000';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '10001';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '10010';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '10011';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '10100';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '10101';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '10110';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '10111';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '11000';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '11001';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '11010';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '11011';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '11100';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '11101';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '11110';})) >= 1);
\$test->expect(count(array_filter(\$chromosomes, function (\$c) {return \$c === '11111';})) >= 1);
});
});``````

# Kata in PHP #8 - Training JS #36: methods of Math---kata author's lover:random()

## Kata

Training JS #36: methods of Math---kata author's lover:random() (7kyu)

``````function rnd_code() {
\$result = "";
\$upcase = str_split("ABCDEFGHIJKLM");
\$symbols = str_split("~!@#\$%^&*");
for (\$i = 0; \$i < 2; \$i++) {
\$result .= \$upcase[~~(lcg_value() * count(\$upcase))];
}
for (\$i = 0; \$i < 4; \$i++) {
\$result .= ~~(10 * lcg_value());
}
for (\$i = 0; \$i < 2; \$i++) {
\$result .= \$symbols[~~(lcg_value() * count(\$symbols))];
}
return \$result;
}

\$test->describe('The \'rnd_code\' function', function () {
\$GLOBALS['test']->it("should work for a basic test", function () {
\$yourcode = rnd_code();
\$GLOBALS['test']->expect(is_string(\$yourcode), "The result should be string");
\$GLOBALS['test']->expect(strlen(\$yourcode) === 8, "The length should be 8");
\$yourcode = str_split(\$yourcode);
\$GLOBALS['test']->expect(array_search(\$yourcode[0], str_split("ABCDEFGHIJKLM")) !== false, "1st char should generate from A-M");
\$GLOBALS['test']->expect(array_search(\$yourcode[1], str_split("ABCDEFGHIJKLM")) !== false, "2nd char should generate from A-M");
\$GLOBALS['test']->expect(array_search(\$yourcode[2], str_split("0123456789")) !== false, "3rd char should generate from 0-9");
\$GLOBALS['test']->expect(array_search(\$yourcode[3], str_split("0123456789")) !== false, "4th char should generate from 0-9");
\$GLOBALS['test']->expect(array_search(\$yourcode[4], str_split("0123456789")) !== false, "5th char should generate from 0-9");
\$GLOBALS['test']->expect(array_search(\$yourcode[5], str_split("0123456789")) !== false, "6th char should generate from 0-9");
\$GLOBALS['test']->expect(array_search(\$yourcode[6], str_split("~!@#\$%^&*")) !== false, "7th char should generate from ~!@#\$%^&*");
\$GLOBALS['test']->expect(array_search(\$yourcode[7], str_split("~!@#\$%^&*")) !== false, "8th char should generate from ~!@#\$%^&*");
});
\$GLOBALS['test']->it('should work for 100 random tests', function () {
\$codes = [];
for (\$i = 0; \$i < 100; \$i++) {
array_push(\$codes, rnd_code());
}
for (\$i = 0; \$i < 100; \$i++) {
for (\$k = 0; \$k < \$i; \$k++) {
\$GLOBALS['test']->assert_not_equals(\$codes[\$i], \$codes[\$k], "Your function should not generate duplicate verification codes");
}
}
});
});``````

# Kata in PHP #7 - Recursion #2 - Fibonacci

## Kata

Recursion #2 - Fibonacci (7kyu)

``````function fibonacci(\$n) {
return \$n === 1 || \$n === 2 ? 1 : fibonacci(\$n - 1) + fibonacci(\$n - 2);
}

\$test->describe('fibonacci(\$n)', function () {
\$GLOBALS['test']->it('should work for some fixed tests', function () {
\$GLOBALS['test']->assert_equals(fibonacci(1), 1);
\$GLOBALS['test']->assert_equals(fibonacci(2), 1);
\$GLOBALS['test']->assert_equals(fibonacci(3), 2);
\$GLOBALS['test']->assert_equals(fibonacci(4), 3);
\$GLOBALS['test']->assert_equals(fibonacci(5), 5);
\$GLOBALS['test']->assert_equals(fibonacci(6), 8);
\$GLOBALS['test']->assert_equals(fibonacci(7), 13);
\$GLOBALS['test']->assert_equals(fibonacci(8), 21);
\$GLOBALS['test']->assert_equals(fibonacci(9), 34);
\$GLOBALS['test']->assert_equals(fibonacci(10), 55);
\$GLOBALS['test']->assert_equals(fibonacci(11), 89);
\$GLOBALS['test']->assert_equals(fibonacci(12), 144);
\$GLOBALS['test']->assert_equals(fibonacci(13), 233);
\$GLOBALS['test']->assert_equals(fibonacci(14), 377);
\$GLOBALS['test']->assert_equals(fibonacci(15), 610);
\$GLOBALS['test']->assert_equals(fibonacci(16), 987);
\$GLOBALS['test']->assert_equals(fibonacci(17), 1597);
\$GLOBALS['test']->assert_equals(fibonacci(18), 2584);
\$GLOBALS['test']->assert_equals(fibonacci(19), 4181);
\$GLOBALS['test']->assert_equals(fibonacci(20), 6765);
});
});``````

### Hello C#!

Hello C# in main mode.

Code
Diff
• ``````class Kata{
public static void Main(){
string language = "C#";
System.Console.WriteLine("Hello, {0}!",language);
}
}``````
•  1 − ```string language = "C#"; ``` 2 − ```System.Console.WriteLine("Hello, {0}!",language); ``` 1 + ```class Kata{ ``` 2 + ``` public static void Main(){ ``` 3 + ``` string language = "C#"; ``` 4 + ``` System.Console.WriteLine("Hello, {0}!",language); ``` 5 + ``` } ``` 6 + ```} ```

### Printing lowercase

Fundamentals

In this kata you should print a given string in lowercase fashion.

``````#include<stdio.h>
#include<string.h>

int main() {
char* my_string="Hello, LOWERCASE C!\n";
strlwr(my_string);
printf(my_string);
return 0;
}``````

# Kata in PHP #6 - Random case

## Kata

Random Case (7kyu)

``````function random_case(\$string) {
return implode(array_map(function (\$char) {
return lcg_value() < 0.5 ? strtoupper(\$char) : strtolower(\$char);
}, str_split(\$string)));
}

\$test->describe("The random_case function", function () {
\$GLOBALS['test']->it("should not return a fully lowercase string", function () {
for (\$i = 0; \$i < 25; \$i++) {
\$random_string = \$GLOBALS['test']->random_token();
echo "Random String: \"\$random_string\"<br />";
\$output = random_case(\$random_string);
echo "Output: \"\$output\"<br />";
\$GLOBALS['test']->assert_not_equals(\$output, \$random_string);
}
});
\$GLOBALS['test']->it("should not return a fully uppercase string", function () {
for (\$i = 0; \$i < 25; \$i++) {
\$random_string = strtoupper(\$GLOBALS['test']->random_token());
echo "Random String: \"\$random_string\"<br />";
\$output = random_case(\$random_string);
echo "Output: \"\$output\"<br />";
\$GLOBALS['test']->assert_not_equals(\$output, \$random_string);
}
});
\$GLOBALS['test']->it("should return a string consisting about 50% of lowercase and uppercase characters for very long strings", function () {
\$lowercase = str_split("abcdefghijklmnopqrstuvwxyz");
\$random_lowercase_string = "";
for (\$i = 0; \$i < 1000; \$i++) {
\$random_lowercase_string .= \$lowercase[~~(lcg_value() * count(\$lowercase))];
}
echo "Input: \$random_lowercase_string<br />";
\$output = random_case(\$random_lowercase_string);
echo "Output: \$output<br />";
echo "Number of lowercase characters in output: " . count(array_filter(str_split(\$output), function (\$char) {
return \$char === strtolower(\$char);
})) . "<br />";
\$GLOBALS['test']->expect(count(array_filter(str_split(\$output), function (\$char) {
return \$char === strtolower(\$char);
})) > 400 && count(array_filter(str_split(\$output), function (\$char) {
return \$char === strtolower(\$char);
})) < 600);
echo "Number of uppercase characters in output: " . count(array_filter(str_split(\$output), function (\$char) {
return \$char === strtoupper(\$char);
})) . "<br />";
\$GLOBALS['test']->expect(count(array_filter(str_split(\$output), function (\$char) {
return \$char === strtoupper(\$char);
})) > 400 && count(array_filter(str_split(\$output), function (\$char) {
return \$char === strtoupper(\$char);
})) < 600);
});
});``````