def base_to10_u(base, nums):
def ufunc(acc_idx_rst):
(acc, idx, rst) = acc_idx_rst
if [] == rst: return None
addon = rst[-1] * (base ** idx)
return (acc + addon, (acc + addon, idx + 1, rst[:-1]))
return util.head_or(0, unfold_right_i(ufunc, (0, 0, nums)))
def split_at_u(num, lst):
def ufunc(wss_zss_ndx):
((wss, zss), ndx) = wss_zss_ndx
if [] == zss or num <= ndx: return None
return ((wss + [zss[0]], zss[1:]), ((wss + [zss[0]], zss[1:]),
ndx + 1))
return util.head_or(([], lst), unfold_right_i(ufunc, (([], lst), 0)))
def unzip_u(ziplst):
def ufunc(acc_rst):
(acc, rst) = acc_rst
if [] == rst: return None
return ([acc[0] + (rst[0][0],), acc[1] + (rst[0][1],)],
([acc[0] + (rst[0][0],), acc[1] + (rst[0][1],)], rst[1:]))
return util.head_or([(), ()], unfold_right_i(ufunc,
([(), ()], ziplst)))
def anyall_u(pred, lst):
func = lambda acc, e: (acc[0] or pred(e), acc[1] and pred(e))
def ufunc(acc_rst):
(acc, rst) = acc_rst
if [] == rst: return None
return (func(acc, rst[0]), (func(acc, rst[0]), rst[1:]))
return util.head_or((False, True), unfold_right_i(ufunc,
((False, True), lst)))
def nth_u(idx, lst):
def gen_func(el, acc, ndx):
return el if idx == ndx else acc
def ufunc(acc_ndx_rst):
(acc, ndx, rst) = acc_ndx_rst
if [] == rst: return None
return (gen_func(rst[0], acc, ndx), (gen_func(rst[0], acc, ndx),
ndx + 1, rst[1:]))
return util.head_or(None, unfold_right_i(ufunc, (None, 0, lst)))
def index_find_u(data, lst, idx=0):
def gen_func(el, idx_fnd, ndx):
return (ndx, el) if -1 == idx_fnd[0] and data == el else idx_fnd
def ufunc(acc_ndx_rst):
(acc, ndx, rst) = acc_ndx_rst
if [] == rst: return None
return (gen_func(rst[0], acc, ndx), (gen_func(rst[0], acc, ndx),
ndx + 1, rst[1:]))
return util.head_or(-1, unfold_right_i(ufunc, ((-1, None), 0, lst)))
def lcm_u(nums):
import fractions
if [] == nums: return 0
def ufunc(acc_rst):
(acc, rst) = acc_rst
if [] == rst: return None
cur = acc * int(rst[0] / fractions.gcd(acc, rst[0]))
return (cur, (cur, rst[1:]))
return util.head_or(nums[0], unfold_right_i(ufunc,
(nums[0], nums[1:])))
def interleave_u(xss, yss):
len_short = len(xss) if len(xss) < len(yss) else len(yss)
init = xss[len_short:] + yss[len_short:]
def ufunc(acc_wss_rst):
(acc, wss, rst) = acc_wss_rst
if [] == rst: return None
return ([wss[-1], rst[0]] + acc,
([wss[-1], rst[0]] + acc, wss[:-1], rst[1:]))
return util.head_or(init, unfold_right_i(ufunc,
(init, xss[:len_short], list(reversed(yss[:len_short])))))
def is_ordered_u(xss, key_func=None, reverse=False):
if None == key_func: key_func = lambda x: x
_flip_le = _flip_func(operator.le, reverse)
#if 1 2 > len(xss): return True
def ufunc(acc_rst):
(acc, rst) = acc_rst
if 2 > len(rst): return None
return (acc and _flip_le(rst[0], rst[1]),
(acc and _flip_le(rst[0], rst[1]), rst[1:]))
return util.head_or(True, unfold_right_i(ufunc, (True, xss)))
def partition_u(pred, lst):
def gen_func(el, lst0_lst1):
(lst0, lst1) = lst0_lst1
return (lst0 + [el], lst1) if pred(el) else (lst0, lst1 + [el])
def ufunc(wss_zss_rst):
((wss, zss), rst) = wss_zss_rst
if [] == rst: return None
return (gen_func(rst[0], (wss, zss)),
(gen_func(rst[0], (wss, zss)), rst[1:]))
return util.head_or(([], []), unfold_right_i(ufunc, (([], []), lst)))
def minmax_u(lst):
if [] == lst: raise Exception('empty list')
def gen_func(el, lo_hi):
(lo, hi) = lo_hi
return (el, hi) if lo > el else (lo, el) if hi < el else (lo, hi)
def ufunc(lo_hi_rst):
((lo, hi), rst) = lo_hi_rst
if [] == rst: return None
return (gen_func(rst[0], (lo, hi)), (gen_func(rst[0], (lo, hi)),
rst[1:]))
return util.head_or((lst[0], lst[0]), unfold_right_i(ufunc,
((lst[0], lst[0]), lst[1:])))
def expt_u(base, num):
def ufunc(acc_cnt):
if 1 > acc_cnt[1]: return None
return (acc_cnt[0] * base, (acc_cnt[0] * base, acc_cnt[1] - 1))
return util.head_or(0.0, unfold_right_i(ufunc, (1, num)))
def concat_u(nlsts):
def ufunc(acc_rst):
(acc, rst) = acc_rst
return None if [] == rst else (rst[0] + acc, (rst[0] + acc, rst[1:]))
return util.head_or([], unfold_right_i(ufunc,
([], list(reversed(nlsts)))))
def numseq_math_u(op, hi, lo):
init = 0 if op in [operator.add, operator.sub] else 1
def ufunc(acc_cur):
(acc, cur) = acc_cur
return None if hi < cur else (op(acc, cur), (op(acc, cur), cur + 1))
return util.head_or(init, unfold_right_i(ufunc, (init, lo)))
def append_u(xss, yss):
def ufunc(acc_rst):
(acc, rst) = acc_rst
if [] == rst: return None
return (acc + [rst[0]], (acc + [rst[0]], rst[1:]))
return util.head_or(xss[:], unfold_right_i(ufunc, (xss[:], yss)))
def fib_u(num):
def ufunc(s0_s1_cnt):
(s0, s1, cnt) = s0_s1_cnt
return None if 0 > cnt else (s0, (s1, s0 + s1, cnt - 1))
return util.head_or(0, unfold_right_i(ufunc, (0, 1, num)))
def length_u(lst):
def ufunc(cnt_rst):
if [] == cnt_rst[1]: return None
return (cnt_rst[0] + 1, (cnt_rst[0] + 1, cnt_rst[1][1:]))
return util.head_or(0, unfold_right_i(ufunc, (0, lst)))