# -*- coding: utf-8 -*-
from __future__ import print_function
from __future__ import absolute_import
try:
from traits.api import Undefined
except ImportError:
# no traits: use None
Undefined = None
[docs]
def list_to_sequence(item, src_param, value, dst_param, dst_value):
''' item-th element of list value
'''
return value[item]
[docs]
def sequence_to_list(item, src_param, value, dst_param, dst_value):
''' set the value value as item-th element of list dst_value
'''
if dst_value is None:
dst_value = [Undefined] * (item + 1)
if len(dst_value) <= item:
dst_value += [Undefined] * (item + 1 - len(dst_value))
dst_value[item] = value
return dst_value
[docs]
def append_to_list(src_param, value, dst_param, dst_value):
''' appends the value value at the end of list dst_value
'''
if dst_value is None:
dst_value = []
dst_value.append(value)
return dst_value
[docs]
def list_all_but_one(item, src_param, value, dst_param, dst_value):
''' remove item-th element from the input list.
Useful in a leave-one-out pattern
'''
return value[:item] + value[item + 1:]
[docs]
def list_cv_train_fold(fold, nfolds, src_param, value, dst_param, dst_value):
''' take all but fold-th division in a list divided into nfold folds.
Useful in a nfolds cross-validation pattern
'''
nitems = len(value)
fold_size = nitems // nfolds
nsupp = nitems % nfolds
begin = fold_size * fold
begin += min(begin, nsupp)
end = fold_size * (fold + 1)
end += min(end, nsupp)
return value[:begin] + value[end:]
[docs]
def list_cv_test_fold(fold, nfolds, src_param, value, dst_param, dst_value):
''' take fold-th division in a list divided into nfold folds.
Useful in a nfolds cross-validation pattern
'''
nitems = len(value)
fold_size = nitems // nfolds
nsupp = nitems % nfolds
begin = fold_size * fold
begin += min(begin, nsupp)
end = fold_size * (fold + 1)
end += min(end, nsupp)
return value[begin:end]
[docs]
def list_cat(item, src_param, value, dst_param, dst_value):
''' concatenates lists: extend value (list) after dst_value
'''
if dst_value is None:
dst_value = []
dst_value += value
return dst_value
[docs]
def sequence_max(shift, src_param, value, dst_param, dst_value):
''' get maximum value from a list
'''
#print('shift', shift,
#'src_param:', src_param,
#'dst_param:', dst_param,
#'dst_value:', dst_value,
#'value', value)
if dst_value is None:
dst_value = type(value)(0) + shift
dst_value = max(dst_value, value + shift)
return dst_value
[docs]
def sequence_min(shift, src_param, value, dst_param, dst_value):
''' get minimum value from a list
'''
if dst_value is None:
dst_value = type(value)(value + shift)
dst_value = min(dst_value, value + shift)
return dst_value
[docs]
def sequence_sum(shift, src_param, value, dst_param, dst_value):
''' sum value from a list
'''
if dst_value is None:
dst_value = type(value)(0) + shift
dst_value += value
return dst_value
