Headline

Map a tuple of sequences into a sequence of tuples

Illustration

In Language:Haskell, the basic zip function is of the following type:

> :t zip
zip :: [a] -> [b] -> [(a, b)]

Thus, the zip function takes two lists of possibly different element types and returns a list of pairs. Here is an illustrative application of zip to build pairs of characters with associated ASCII codes:

> zip ['A','B','C'] [65,66,67]
[('A',65),('B',66),('C',67)]

There exist further variation on zipping. For instance, there is also a zipWith function which applies an argument function to pairs rather than constructing pairs. For instance, consider two lists of operands for addition; pairwise addition can be applied as follows:

> :t zipWith
zipWith :: (a -> b -> c) -> [a] -> [b] -> [c]
> zipWith (+) [1,2,3] [4,5,6] 
[5,7,9]

For what it matters, the basic zip function is defined as follows:

zip :: [a] -> [b] -> [(a, b)]
zip = zipWith (,) -- apply pair construction

Headline

The functional programming language Haskell

Details

101wiki hosts plenty of Haskell-based contributions. This is evident from corresponding back-links. More selective sets of Haskell-based contributions are organized in themes: Theme:Haskell data, Theme:Haskell potpourri, and Theme:Haskell genericity. Haskell is also the language of choice for a course supported by 101wiki: Course:Lambdas_in_Koblenz.

Illustration

The following expression takes the first 42 elements of the infinite list of natural numbers:

> take 42 [0..]
[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41]

In this example, we leverage Haskell's lazy evaluation.