30 seconds of PHP

Math

Click on a snippet's name to view its code.

approximatelyEqual

Checks if two numbers are approximately equal to each other.

Use abs() to compare the absolute difference of the two values to $epsilon. Omit the third parameter, $epsilon, to use a default value of 0.001.

average

Returns the average of two or more numbers.

Use array_sum() for all the values in $items and return the result divided by their count().

clampNumber

Clamps $num within the inclusive range specified by the boundary values $a and $b.

If $num falls within the range, return $num. Otherwise, return the nearest number in the range, using min() and max().

factorial

Calculates the factorial of a number.

Use recursion. If $n is less then or equal to 1, return 1. Otherwise, return the product of $n and the factorial of $n -1. Throws an exception if $n is a negative number.

fibonacci

Generates an array, containing the Fibonacci sequence, up until the nth term.

Create an empty array, initializing the first two values (0 and 1). Loop from 2 through $n and add values into the array, using the sum of the last two values.

gcd

Calculates the greatest common divisor between two or more numbers.

Use recursion. Use array_reduce() with the gcd function to appy to all elements in the $numbers list. Base case is when y equals 0. In this case, return x. Otherwise, return the gcd of y and the remainder of the division x/y.

isEven

Returns true if the given number is even, false otherwise.

Checks whether a number is odd or even using the modulo (%) operator. Returns true if the number is even, false if the number is odd.

isPrime

Checks if the provided integer is a prime number.

Check numbers from 2 to the square root of the given number. Return false if any of them divides the given number, else return true, unless the number is less than 2.

lcm

Returns the least common multiple of two or more numbers.

Use the greatest common divisor (GCD) formula and the fact that lcm(x,y) = x * y / gcd(x,y) to determine the least common multiple. The GCD formula uses recursion.

maxN

Returns the maximum value from the provided array.

Use array_filter() and max() to find the maximum value in an array.

median

Returns the median of an array of numbers.

Find the middle of the array, use sort() to sort the values. Return the number at the midpoint if the array's length is odd, otherwise the average of the two middle numbers.

minN

Returns the minimum value from the provided array.

Use array_filter() and min() to find the minimum value in an array.