apply

The apply function is typically used for Pairs represented in a List. The apply function accesses each member of a List using integer indices 0 to n-1 when n is the number of elements in the List. The apply function with a List argument is equivalent to:

(setq A '( 1 4 5 6 7 3 ) )

(apply + A)

or

( + (+ ( + ( + (+ A[0] A[1] ) A[2] ) A[3] ) A[4] ) A[5] )

or

(+ A[0] A[1] A [2] A[3] A[4] A[5] )

As you can see, the apply function is a much simpler form. Note that the apply function will not access the cdr (tail) of a List:

(setq A '( 1 4 5 6 7 3 . 100 ) )

(apply + A)

Returns: 26

(apply function pair)

Here are a number of links to Lambda coding examples which contain this instruction in various use cases.

Example_Pair_apply_009

This example defines a Pair containing Integer values. Then it uses the apply function to add all the values in the Vector.

This example defines a Pair containing Text values. Then it uses the apply function to append all the values in the Pair.

Here are the links to the data types of the function arguments.

Here are also a number of links to functions having arguments with any of these data types.

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