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List comprehension is a syntactic construct available in some programming languages for creating a list based on existing lists. It follows the form of the mathematical set-builder notation (set comprehension) as distinct from the use of map and filter functions.
Here, the list [0..] represents , x^2>3 represents the predicate, and 2*x represents the output expression.. List comprehensions give results in a defined order (unlike the members of sets); and list comprehensions may generate the members of a list in order, rather than produce the entirety of the list thus allowing, for example, the previous Haskell definition of the members of an infinite list.
For example, to perform an element by element sum of two arrays, a and b to produce a third c, it is only necessary to write c = a + b 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)
When a programming languages has statements, they typically have conventions for: . statement separators; statement terminators; and; line continuation; A statement separator demarcates the boundary between two separate statements.
(with-hash-table-iterator (entry-generator phone-book) (loop do (multiple-value-bind (has-entry key value) (entry-generator) (if has-entry (format T "~&~s => ~s" key value) (loop-finish))))) It is easy to construct composite abstract data types in Lisp, using structures or object-oriented programming features, in conjunction with lists, arrays ...
The example above, of list comprehension in the sin() function, is a useful feature in of itself. By using implicit parallelism, languages effectively have to provide such useful constructs to users simply to support required functionality (a language without a decent for loop, for example, is one few programmers will use).
Iterative for-loops can contain multiple conditionals, such as for(int i = 0; i < 10 && somethingTrue; i++). This is a legacy of C, where the for statement is basically syntactic sugar for a while statement. The getter and setter of a property may implement separate interfaces.
modified_identifier_list «As «non_array_type««array_rank_specifier»» (multiple declarator); valid declaration statements are of the form Dim declarator_list , where, for the purpose of semantic analysis, to convert the declarator_list to a list of only single declarators: