sagemathgh-39337: a few fixes for ruff PLC

    
this is about using `.items()` when possible

here in various folders

### 📝 Checklist

- [x] The title is concise and informative.
- [x] The description explains in detail what this PR is about.
    
URL: sagemath#39337
Reported by: Frédéric Chapoton
Reviewer(s): David Coudert, Martin Rubey

src/sage/interfaces/lie.py

@@ -285,6 +285,8 @@
 #                  https://www.gnu.org/licenses/
 #
 ##########################################################################
+from itertools import chain
+import os
 
 from .expect import Expect, ExpectElement, ExpectFunction, FunctionElement
 from sage.interfaces.interface import AsciiArtString
@@ -293,7 +295,6 @@
 from sage.misc.sage_eval import sage_eval
 from sage.interfaces.tab_completion import ExtraTabCompletion
 from sage.misc.instancedoc import instancedoc
-import os
 
 
 COMMANDS_CACHE = '%s/lie_commandlist_cache.sobj' % DOT_SAGE
@@ -448,9 +449,7 @@ def _read_info_files(self, use_disk_cache=True):
         info.close()
 
         # Build the list of all possible command completions
-        l = []
-        for key in commands:
-            l += commands[key]
+        l = list(chain(*commands.values()))
 
         # Save the data
         self._tab_completion_dict = commands
@@ -574,7 +573,7 @@ def version(self) -> str:
         EXAMPLES::
 
             sage: lie.version() # optional - lie
-            '2.2'
+            '2...'
         """
         return lie_version()
 
@@ -943,7 +942,7 @@ def lie_version():
 
         sage: from sage.interfaces.lie import lie_version
         sage: lie_version() # optional - lie
-        '2.2'
+        '2...'
     """
     with open(os.path.join(LIE_INFO_DIR, 'INFO.0')) as f:
         lines = f.readlines()

src/sage/knots/free_knotinfo_monoid.py

@@ -339,8 +339,7 @@ def hp_mirr(hp):
                 if SymmetryMutant.concordance_inverse in hp_sym.keys():
                     hp_sym[SymmetryMutant.concordance_inverse] = hpm
 
-            for sym_mut in hp_sym.keys():
-                hps = hp_sym[sym_mut]
+            for sym_mut, hps in hp_sym.items():
                 if hps.divides(hpoly):
                     Kgen = self((K, sym_mut))
                     h = hpoly // hps

src/sage/knots/link.py

@@ -1181,25 +1181,26 @@ def _khovanov_homology_cached(self, height, ring=ZZ):
         for st in states:
             i, j = st[3], st[4]
             if j == height:
-                if (i,j) in bases:
-                    bases[i,j].append(st)
+                if (i, j) in bases:
+                    bases[i, j].append(st)
                 else:
-                    bases[i,j] = [st]
+                    bases[i, j] = [st]
         complexes = {}
-        for (i, j) in bases:
-            if (i+1, j) in bases:
-                m = matrix(ring, len(bases[(i,j)]), len(bases[(i+1,j)]))
+        for (i, j), bij in bases.items():
+            if (i + 1, j) in bases:
+                m = matrix(ring, len(bij), len(bases[(i + 1, j)]))
                 for ii in range(m.nrows()):
-                    V1 = bases[(i,j)][ii]
+                    V1 = bij[ii]
                     for jj in range(m.ncols()):
-                        V2 = bases[(i+1, j)][jj]
+                        V2 = bases[(i + 1, j)][jj]
                         V20 = V2[0]
-                        difs = [index for index,value in enumerate(V1[0]) if value != V20[index]]
+                        difs = [index for index, value in enumerate(V1[0])
+                                if value != V20[index]]
                         if len(difs) == 1 and not (V2[2].intersection(V1[1]) or V2[1].intersection(V1[2])):
-                            m[ii,jj] = (-1)**sum(V2[0][x] for x in range(difs[0]+1, ncross))
+                            m[ii, jj] = (-1)**sum(V2[0][x] for x in range(difs[0]+1, ncross))
                             # Here we have the matrix constructed, now we have to put it in the dictionary of complexes
             else:
-                m = matrix(ring, len(bases[(i,j)]), 0)
+                m = matrix(ring, len(bij), 0)
             complexes[i] = m.transpose()
             if (i-1, j) not in bases:
                 complexes[i-1] = matrix(ring, len(bases[(i,j)]), 0)

src/sage/misc/sage_input.py

@@ -1405,10 +1405,10 @@ def __call__(self, *args, **kwargs):
             sage: sie(4)
             {call: {atomic:3}({atomic:4})}
         """
-        args = [self._sie_builder(_) for _ in args]
-        for k in kwargs:
-            kwargs[k] = self._sie_builder(kwargs[k])
-        return SIE_call(self._sie_builder, self, args, kwargs)
+        new_args = [self._sie_builder(arg) for arg in args]
+        new_kwargs = {key: self._sie_builder(val)
+                      for key, val in kwargs.items()}
+        return SIE_call(self._sie_builder, self, new_args, new_kwargs)
 
     def __getitem__(self, key):
         r"""

src/sage/modular/modsym/relation_matrix.py

@@ -243,8 +243,8 @@ def T_relation_matrix_wtk_g0(syms, mod, field, sparse):
                 v[j0] += s0
             else:
                 v[j0] = s0
-        for j0 in v:
-            entries[(row, j0)] = v[j0]
+        for j0, vj0 in v.items():
+            entries[(row, j0)] = vj0
         row += 1
 
     MAT = MatrixSpace(field, row, len(syms), sparse=True)

src/sage/monoids/string_monoid_element.py

@@ -358,12 +358,11 @@ def coincidence_index(self, prec=0):
                 char_dict[i] = 1
         nn = 0
         ci_num = 0
-        for i in char_dict.keys():
-            ni = char_dict[i]
+        for ni in char_dict.values():
             nn += ni
-            ci_num += ni*(ni-1)
-        ci_den = nn*(nn-1)
-        return RR(ci_num)/ci_den
+            ci_num += ni * (ni - 1)
+        ci_den = nn * (nn - 1)
+        return RR(ci_num) / ci_den
 
     def character_count(self):
         r"""

src/sage/plot/colors.py

@@ -1022,8 +1022,8 @@ def __init__(self):
             148
         """
         # Convert the colors_dict defined above to Color instances.
-        for k in colors_dict:
-            self[k] = Color(colors_dict[k])
+        for k, col in colors_dict.items():
+            self[k] = Color(col)
 
     def __getattr__(self, name):
         """

src/sage/plot/primitive.py

@@ -179,10 +179,10 @@ def options(self):
             A = self._allowed_options()
             t = False
             K = list(A) + ['xmin', 'xmax', 'ymin', 'ymax', 'axes']
-            for k in O.keys():
+            for k, Ok in O.items():
                 if k not in K:
                     do_verify = False
-                    verbose(f"WARNING: Ignoring option '{k}'={O[k]}",
+                    verbose(f"WARNING: Ignoring option '{k}'={Ok}",
                             level=0)
                     t = True
             if t:
@@ -195,8 +195,8 @@ def options(self):
 
         if 'hue' in O:
             t = O['hue']
-            if not isinstance(t, (tuple,list)):
-                t = [t,1,1]
+            if not isinstance(t, (tuple, list)):
+                t = [t, 1, 1]
             O['rgbcolor'] = hue(*t)
             del O['hue']
         return O