Operations on Complex Types

The same operators as for the arithmetical operations can also be used on some other data types. For example, by “adding” two arrays you can concatenate them: ({ 7, 6, 3 }) + ({ 6, 19 }) gives the result ({ 7, 6, 3, 6, 19 }).

Here is a complete table of what happens when you use the arithmetic operators with values of the various types in Pike:

Operation	Returned type	result
`int + int`	int	the sum of the two values
`float + int` `int + float` `float + float`	float	the sum of the two values
`string + string` `int + string` `float + string` `string + int` `string + float`	string	In this case, any int or float is first converted to a string. Then the two strings are concatenated and the resulting string is returned.
`array + array`	array	The two arrays are concatenated into a new array and that new array is returned.
`mapping + mapping`	mapping	A mapping with all the index-value pairs from both mappings is returned. If an index is present in both mappings the index-value pair from the right mapping will be used.
`multiset + multiset`	multiset	A multiset with all the members from both multisets is returned.
`int - int`	int	The right value subtracted from the left.
`float - int` `int - float` `float - float`	float	The right value subtracted from the left.
`string - string`	string	A copy of the left string with all occurrences of the right string removed.
`array - array`	array	A copy of the right array with all elements present in the right array removed. Example: `({2,1,4,5,3,6,7}) - ({3,5,1})` will return `({2,4,6,7})`.
`mapping - mapping`	mapping	A new mapping with all index-value pairs from the left mapping, except those indexes that are also present in the right mapping.
`multiset - multiset`	multiset	A copy of the left multiset without any member present in the left multiset.
`- int`	int	Same as 0 - int.
`- float`	float	Same as 0 - float.
`int * int`	int	the product of the two values
`float * int` `int * float` `float * float`	float	the product of the two values
`array(string) * string`	string	All the strings in the array are concatenated with the string on the right in between each string. Example: `({"foo,"bar})*"-"` will return `"foo-bar".`
`int / int`	int	The right integer divided by the left integer rounded towards minus infinity.
`float / int` `int / float` `float / float`	float	The right value divided by the left value.
`string / string`	array(string)	In symmetry with the multiplication operator, the division operator can split a string into pieces. The right string will be split at every occurrence of the right string and an array containing the results will be returned. Example: `"foo-bar"/"-"` will return `({"foo","bar"})`
`int % int`	int	The rest of a division. If `a` and `b` are integers, `a%b` is the same as `a-(a/b)*b`
`float % float` `int % float` `float % int`	float	The rest of a division. If `a` and `b` are floats, `a%b` is the same as `a-floor(a/b)*b`