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In JavaScript an object is a mapping from property names to values—that is, an associative array with one caveat: the keys of an object must be either a string or a symbol (native objects and primitives implicitly converted to a string keys are allowed).
If an object is compared with a number or string, JavaScript attempts to return the default value for the object. An object is converted to a primitive String or Number value, using the .valueOf() or .toString() methods of the object.
Go's foreach loop can be used to loop over an array, slice, string, map, or channel. Using the two-value form gets the index/key (first element) and the value (second element): for index , value := range someCollection { // Do something to index and value }
In PHP and R, all arrays can be associative, except that the keys are limited to integers and strings. In JavaScript (see also JSON), all objects behave as associative arrays with string-valued keys, while the Map and WeakMap types take arbitrary objects as keys. In Lua, they are used as the primitive building block for all data structures.
In object-oriented programming, the iterator pattern is a design pattern in which an iterator is used to traverse a container and access the container's elements. The iterator pattern decouples algorithms from containers; in some cases, algorithms are necessarily container-specific and thus cannot be decoupled.
PHP generally follows C syntax, with exceptions and enhancements for its main use in web development, which makes heavy use of string manipulation. PHP variables must be prefixed by "$". This allows PHP to perform string interpolation in double quoted strings, where backslash is supported as an escape character.
String representation Object copy Value equality Object comparison Hash code Object ID Human-readable Source-compatible ABAP Objects — APL (Dyalog) ⍕x ⎕SRC x ⎕NS x: x = y — C++ x == y [52] pointer to object can be converted into an integer ID: C# x.ToString() x.Clone() x.Equals(y) x.CompareTo(y) x.GetHashCode()
Some object-oriented languages such as C#, C++ (later versions), Delphi (later versions), Go, Java (later versions), Lua, Perl, Python, Ruby provide an intrinsic way of iterating through the elements of a collection without an explicit iterator. An iterator object may exist, but is not represented in the source code. [4] [6]