strtoupper

Returns the argument provided with all alphabetic characters converted to uppercase.

PHP

echo strtoupper('Ruby is pure OO');
// => RUBY IS PURE OO

Ruby

puts 'Ruby is pure OO'.upcase;
# => RUBY IS PURE OO

array_change_key_case

This function changes all keys in an array by returning an array with all keys from argument lowercased or uppercased. Numbered indices are left as is.

PHP

$input_array = array('FirSt' => 1, 'SecOnd' => 4);
print_r( array_change_key_case($input_array, CASE_UPPER) );
// => array('FIRST' => 1, 'SECOND' => 4);

To replicate this functionality in Ruby, we need to use a Hash object, since arrays in Ruby don’t use associative key/value pairs.

Ruby

hash = {'FirSt' => 1, 'SecOnd' => 4}
 
result = hash.inject({}) do |hash, keys|
  hash[keys[0].upcase] = keys[1]
  hash
end
p result
# => { 'FIRST' => 1, 'SECOND' => 4 }

addslashes

Addslashes takes a string as an argument, and returns a string with backslashes before characters that need to be quoted in database queries etc. These characters are single quote [ ' ], double quote [ " ], backslash [ \ ] and NULL (the NULL byte).

PHP

echo addslashes("Here's some money for your lunch");
// => Here\'s some money for your lunch

Ruby

puts "Here's some money for your lunch".gsub(/['"\\\x0]/,'\\\\\0');
# => Here\'s some money for your lunch

As you can see above, the easiest way to emulate the PHP function addslashes() in Ruby is to use regular expressions.

abs

Returns the absolute value for a number.

PHP

echo abs(-4.2);
// => 4.2;

Ruby

puts -4.2.abs;
# => 4.2;

acos

Returns the arc cosine of the argument provided in radians.

PHP

echo acos(0.7);
// => 0.79539883018414;

Ruby

puts Math.acos(0.7);
# => 0.79539883018414;

cos

Returns the cosine of the argument provided in radians.

PHP

echo cos(0.5);
// => 0.87758256189037;

Ruby

puts Math.cos(0.5);
# => 0.877582561890373;

ceil

Returns the next highest integer value by rounding up the argument provided.

PHP

echo ceil(4.1);
// => 5

Ruby

puts 4.1.ceil;
# => 5

strtolower

Returns the argument provided with all alphabetic characters converted to lowercase.

PHP

echo strtolower('Ruby is pure OO');
// => ruby is pure oo

Ruby

puts 'Ruby is pure OO'.downcase;
# => ruby is pure oo

sizeof

The sizeof() function is only an alias of count, which returns the number of elements in an array.

For further information about sizeof(), see count().