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In computer programming, foreach loop (or for-each loop) is a control flow statement for traversing items in a collection. foreach is usually used in place of a standard for loop statement . Unlike other for loop constructs, however, foreach loops [ 1 ] usually maintain no explicit counter: they essentially say "do this to everything in this ...
In addition to support for vectorized arithmetic and relational operations, these languages also vectorize common mathematical functions such as sine. For example, if x is an array, then y = sin (x) will result in an array y whose elements are sine of the corresponding elements of the array x. Vectorized index operations are also supported.
Array references are written like function calls, e.g. array(i) rather than array[i]. (Internally in Scala, the former expands into array.apply(i) which returns the reference) Generic types are written as e.g. List[String] rather than Java's List<String>. Instead of the pseudo-type void, Scala has the actual singleton class Unit (see below).
A loop invariant is an assertion which must be true before the first loop iteration and remain true after each iteration. This implies that when a loop terminates correctly, both the exit condition and the loop invariant are satisfied. Loop invariants are used to monitor specific properties of a loop during successive iterations.
The reasoning behind this is that if Array is extended via prototype and Object is kept pristine, for and for-in loops will work as expected on associative 'arrays'. This issue has been brought to the fore by the popularity of JavaScript frameworks that make heavy and sometimes indiscriminate use of prototypes to extend JavaScript's inbuilt types.
Array with all the doubles from 1 to 9 inclusive: my @doubles = map { $_ * 2 } 1 .. 9 ; Array with the names of the customers based in Rio de Janeiro (from array of hashes):
In array languages, operations are generalized to apply to both scalars and arrays. Thus, a+b expresses the sum of two scalars if a and b are scalars, or the sum of two arrays if they are arrays. An array language simplifies programming but possibly at a cost known as the abstraction penalty.
In computer science, a for-loop or for loop is a control flow statement for specifying iteration. Specifically, a for-loop functions by running a section of code repeatedly until a certain condition has been satisfied. For-loops have two parts: a header and a body. The header defines the iteration and the body is the code executed once per ...