Node:SRFI-1 Length Append etc, Next:SRFI-1 Fold and Map, Previous:SRFI-1 Selectors, Up:SRFI-1

39.3.4 Length, Append, Concatenate, etc.

length+ lst

Scheme Procedure

Return the length of the argument list lst. When lst is a circular list, #f is returned.

concatenate list-of-lists	Scheme Procedure
concatenate! list-of-lists	Scheme Procedure

Construct a list by appending all lists in list-of-lists. concatenate! may modify the structure of the given lists in order to produce the result.

append-reverse rev-head tail	Scheme Procedure
append-reverse! rev-head tail	Scheme Procedure

Reverse rev-head, append tail and return the result. This is equivalent to (append (reverse rev-head) tail), but more efficient. append-reverse! may modify rev-head in order to produce the result.

zip lst1 lst2 ...

Scheme Procedure

Return a list as long as the shortest of the argument lists, where each element is a list. The first list contains the first elements of the argument lists, the second list contains the second elements, and so on.

unzip1 lst	Scheme Procedure
unzip2 lst	Scheme Procedure
unzip3 lst	Scheme Procedure
unzip4 lst	Scheme Procedure
unzip5 lst	Scheme Procedure

unzip1 takes a list of lists, and returns a list containing the first elements of each list, unzip2 returns two lists, the first containing the first elements of each lists and the second containing the second elements of each lists, and so on.