Trac #21310: py3: remove itervalues in combinat folder

as a step towards py3, use six to get rid of itervalues

in this ticket, only for the combinat folder

URL: https://trac.sagemath.org/21310
Reported by: chapoton
Ticket author(s): Frédéric Chapoton
Reviewer(s): Jori Mäntysalo

Author: Release Manager

src/sage/combinat/alternating_sign_matrix.py

@@ -30,6 +30,8 @@
 # python3
 from __future__ import division
 
+from six import itervalues
+
 import itertools
 import copy
 from sage.misc.classcall_metaclass import ClasscallMetaclass
@@ -1416,10 +1418,9 @@ def _lattice_initializer(self):
             sage: P.is_lattice()
             True
         """
-        (mts, rels) = MonotoneTriangles(self._n)._lattice_initializer()
-        bij = dict((t, self.from_monotone_triangle(t)) for t in mts)
-        asms, rels = bij.itervalues(), [(bij[a], bij[b]) for (a,b) in rels]
-        return (asms, rels)
+        mts, rels = MonotoneTriangles(self._n)._lattice_initializer()
+        bij = {t: self.from_monotone_triangle(t) for t in mts}
+        return (itervalues(bij), [(bij[a], bij[b]) for (a, b) in rels])
 
     def cover_relations(self):
         r"""

src/sage/combinat/designs/difference_family.py

@@ -51,6 +51,8 @@
 from __future__ import division, print_function
 from __future__ import absolute_import
 
+from six import itervalues
+
 from sage.misc.cachefunc import cached_method
 
 from sage.categories.sets_cat import EmptySetError
@@ -285,7 +287,7 @@ def is_difference_family(G, D, v=None, k=None, l=None, verbose=False):
                 where[gg].add(i)
                 tmp_counter[gg] += 1
 
-        if sum(tmp_counter.itervalues()) != k*(k-1):
+        if sum(itervalues(tmp_counter)) != k * (k - 1):
             if verbose:
                 print("repeated element in the {}-th block {}".format(i,d))
             return False

src/sage/combinat/designs/incidence_structures.py

@@ -40,6 +40,8 @@
 #***************************************************************************
 from __future__ import print_function
 
+from six import itervalues
+
 from sage.misc.cachefunc import cached_method
 
 from sage.rings.all import ZZ
@@ -879,7 +881,7 @@ def degrees(self, size=None):
         In a Steiner triple system, all pairs have degree 1::
 
             sage: S13 = designs.steiner_triple_system(13)
-            sage: all(v == 1 for v in S13.degrees(2).itervalues())
+            sage: all(v == 1 for v in S13.degrees(2).values())
             True
         """
         if size is None:
@@ -1899,7 +1901,7 @@ def is_resolvable(self, certificate=False, solver=None, verbose=0, check=True):
             False
         """
         if self._classes is None:
-            degrees = set(self.degrees().itervalues())
+            degrees = set(itervalues(self.degrees()))
             if len(degrees) != 1:
                 self._classes = False
             else:

src/sage/combinat/designs/orthogonal_arrays.py

@@ -58,6 +58,8 @@
 from __future__ import print_function
 from __future__ import absolute_import
 
+from six import itervalues
+
 from sage.misc.cachefunc import cached_function
 from sage.categories.sets_cat import EmptySetError
 from sage.misc.unknown import Unknown
@@ -1705,7 +1707,7 @@ def OA_n_times_2_pow_c_from_matrix(k,c,G,A,Y,check=True):
                 Hij = set([(Y[i] - Y[j]) * v for v in H])
                 for s in range(2 * G_card):
                     g_to_col_indices[B[i][s] - B[j][s]].append(s)
-                for s1,s2 in g_to_col_indices.itervalues():
+                for s1, s2 in itervalues(g_to_col_indices):
                     v1 = A[i][s1][1] - A[j][s1][1]
                     v2 = A[i][s2][1] - A[j][s2][1]
 

src/sage/combinat/designs/orthogonal_arrays_find_recursive.pyx

@@ -46,6 +46,8 @@ Functions
 """
 from __future__ import print_function, absolute_import
 
+from six import itervalues
+
 from sage.misc.cachefunc import cached_function
 from .orthogonal_arrays import orthogonal_array
 from sage.rings.integer cimport Integer, smallInteger
@@ -798,7 +800,7 @@ cpdef find_brouwer_separable_design(int k,int n):
 # OA(k,n+x)-OA(k,x). Useful in find_brouwer_separable_design
 from sage.combinat.designs.database import QDM as _QDM
 cdef dict ioa_indexed_by_n_minus_x = {}
-for x in _QDM.itervalues():
+for x in itervalues(_QDM):
     for (n,_,_,u),(k,_) in x.items():
         if u>1:
             if not n in ioa_indexed_by_n_minus_x:

src/sage/combinat/finite_state_machine.py

@@ -930,6 +930,8 @@
 #*****************************************************************************
 from __future__ import print_function
 
+from six import itervalues
+
 import collections
 import itertools
 from six.moves import zip_longest
@@ -6729,7 +6731,7 @@ def add_transition(self, *args, **kwargs):
                 if is_FSMTransition(d):
                     return self._add_fsm_transition_(d)
             else:
-                d = next(kwargs.itervalues())
+                d = next(itervalues(kwargs))
             if hasattr(d, 'iteritems'):
                 args = []
                 kwargs = d

src/sage/combinat/matrices/hadamard_matrix.py

@@ -55,6 +55,8 @@
 #*****************************************************************************
 from __future__ import print_function
 
+from six import itervalues
+
 from sage.rings.integer_ring import ZZ
 from sage.rings.integer import Integer
 from sage.matrix.constructor import matrix, block_matrix, block_diagonal_matrix, diagonal_matrix
@@ -296,8 +298,8 @@ def is_hadamard_matrix(M, normalized=False, skew=False, verbose=False):
 
     prod = (M*M.transpose()).dict()
     if (len(prod) != n or
-        set(prod.itervalues()) != {n} or
-        any( (i,i) not in prod for i in range(n) )):
+        set(itervalues(prod)) != {n} or
+        any((i, i) not in prod for i in range(n))):
         if verbose:
             print("The product M*M.transpose() is not equal to nI")
         return False

src/sage/combinat/permutation.py

@@ -228,6 +228,8 @@
 #*****************************************************************************
 from __future__ import print_function, absolute_import
 
+from six import itervalues
+
 from sage.structure.parent import Parent
 from sage.structure.unique_representation import UniqueRepresentation
 from sage.categories.infinite_enumerated_sets import InfiniteEnumeratedSets
@@ -5480,7 +5482,7 @@ def cardinality(self):
             d[i] = d.get(i, 0) + 1
 
         c = factorial(len(lmset))
-        for i in d.itervalues():
+        for i in itervalues(d):
             if i != 1:
                 c //= factorial(i)
         return ZZ(c)

src/sage/combinat/posets/posets.py

@@ -244,6 +244,8 @@
 # python3
 from __future__ import division, print_function, absolute_import
 
+from six import itervalues
+
 import copy
 from sage.misc.cachefunc import cached_method
 from sage.misc.lazy_attribute import lazy_attribute
@@ -6003,8 +6005,8 @@ def is_slender(self):
             d = {}
             for y in self.upper_covers(x):
                 for c in self.upper_covers(y):
-                    d[c] = d.get(c,0) + 1
-            if not all( y < 3 for y in d.itervalues() ):
+                    d[c] = d.get(c, 0) + 1
+            if not all(y < 3 for y in itervalues(d)):
                 return False
         return True
 

src/sage/combinat/words/suffix_trees.py

@@ -10,6 +10,9 @@
 # (at your option) any later version.
 #                  http://www.gnu.org/licenses/
 #*****************************************************************************
+
+from six import iteritems
+
 from sage.structure.sage_object import SageObject
 from sage.graphs.digraph import DiGraph
 from sage.sets.set import Set
@@ -204,8 +207,8 @@ def node_to_word(self, state=0):
         if state == 0:
             return Words(self._alphabet)()
         # We first invert the transition function
-        tf_inv = dict(izip(self._transition_function.itervalues(),
-                            self._transition_function))
+        tf_inv = {b: a for a, b in iteritems(self._transition_function)}
+
         # Starting from the active state,
         # read labels along the unique path to the root.
         (u,letter) = tf_inv[state]
@@ -448,7 +451,7 @@ def to_digraph(self):
             [0 0 0 0 0 0]
         """
         dag = {}
-        for ((u,letter),v) in self._transition_function.iteritems():
+        for ((u, letter), v) in iteritems(self._transition_function):
             dag.setdefault(u, {})[v] = letter
         return DiGraph(dag)
 
@@ -752,7 +755,7 @@ def _find_transition(self, state, letter):
             return ((0, 0), 0)
         else:
             if state in self._transition_function:
-                for ((k,p),s) in self._transition_function[state].iteritems():
+                for ((k,p),s) in iteritems(self._transition_function[state]):
                     if self._letters[k-1] == letter:
                         return ((k,p), s)
             return None
@@ -836,7 +839,7 @@ def to_digraph(self, word_labels=False):
             return DiGraph(d)
         d = self.transition_function_dictionary()
         for u in d:
-            for (v,(i,j)) in d[u].iteritems():
+            for (v, (i, j)) in iteritems(d[u]):
                 if word_labels:
                     d[u][v] = self._word[i:j]
                 elif j is None:
@@ -1122,7 +1125,7 @@ def edge_iterator(self):
         queue = [0]
         while queue:
             v=queue.pop()
-            for ((i,j),u) in self._transition_function[v].iteritems():
+            for ((i,j),u) in iteritems(self._transition_function[v]):
                 yield (v,u,(i-1,j))
                 queue.append(u)
 
@@ -1202,7 +1205,7 @@ def number_of_factors(self,n=None):
                     num_factors += 1
                 if l < n:
                     if self._transition_function[v] != {}:
-                        for ((i,j),u) in self._transition_function[v].iteritems():
+                        for ((i,j),u) in iteritems(self._transition_function[v]):
                             if j is None:
                                 j = self.word().length()
                             if j - i >= n - l:
@@ -1255,7 +1258,7 @@ def factor_iterator(self,n=None):
                 (v,w) = queue.pop()
                 yield w
                 if self._transition_function[v] != {}:
-                    for ((i,j),u) in self._transition_function[v].iteritems():
+                    for ((i,j),u) in iteritems(self._transition_function[v]):
                         if j is None:
                             j = self.word().length()
                         for k in range(i,j):
@@ -1270,7 +1273,7 @@ def factor_iterator(self,n=None):
                     yield w
                 if length_w < n:
                     if self._transition_function[v] != {}:
-                        for ((i,j),u) in self._transition_function[v].iteritems():
+                        for ((i,j),u) in iteritems(self._transition_function[v]):
                             if j is None:
                                 j = self.word().length()
                             if j - i >= n - length_w:
@@ -1333,8 +1336,8 @@ def trie_type_dict(self):
         """
         d = {}
         new_node = len(self._transition_function)
-        for (u, dd) in self._transition_function.iteritems():
-            for (sl, v) in dd.iteritems():
+        for (u, dd) in iteritems(self._transition_function):
+            for (sl, v) in iteritems(dd):
                 w = self._word[sl[0]-1:sl[1]]
                 if w.length() == 1:
                     d[u,w] = v