Node:SRFI-1 Length Append etc, Next:, 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.