#NEGATIVE FILTER ARCHIVE#
#NEGATIVE FILTER FREE#

Many functions on arrays can be created by the use of the foldr() function (which works like foldl, but eating up array elements from the right).

This leads to a style of programming that looks much like algebra, e.g. The array functions mentioned above allow you compose new functions on arrays. One idea is to use functions to create special purpose functions from other functions. A program execution is a call of a function, which in turn might be defined by many other functions.

#NEGATIVE FILTER FREE#

Some of PHP's array functions play a prominent role in so called functional programming languages, where they show up under a slightly different name:Īrray_reduce () -> foldl () ( 'fold left' )įunctional programming is a paradigm which centers around the side-effect free evaluation of functions. 'stringfalse' => string 'false' (length=5) Var_dump ( $array, $filtered1, $filtered2, $filtered3 ) $filtered2 = array_filter ( $array, function( $v ) ) $filtered1 = array_filter ( $array, 'strlen' ) Removes null, null-string - but also FALSE! an integer 0 or a boolean false, be mindful of the result of different filters.

#NEGATIVE FILTER ARCHIVE#

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Negative filter