Trac #33956: some better .join with iterator inside

URL: https://trac.sagemath.org/33956
Reported by: chapoton
Ticket author(s): Frédéric Chapoton
Reviewer(s): David Coudert

src/sage/databases/findstat.py

@@ -4597,8 +4597,8 @@ def name(self, style="singular"):
     "DecoratedPermutations":
     _SupportedFindStatCollection(lambda x: DecoratedPermutation([v if v > 0 else (i if v == 0 else -i)
                                                                  for i, v in enumerate(literal_eval(x.replace("+","0").replace("-","-1")), 1)]),
-                                 lambda x: "[" + ",".join([str(v) if abs(v) != i else ("+" if v > 0 else "-")
-                                                           for i, v in enumerate(x, 1)]) + "]",
+                                 lambda x: "[" + ",".join((str(v) if abs(v) != i else ("+" if v > 0 else "-")
+                                                           for i, v in enumerate(x, 1))) + "]",
                                  DecoratedPermutations,
                                  lambda x: x.size(),
                                  lambda x: isinstance(x, DecoratedPermutation)),

src/sage/doctest/sources.py

@@ -1556,10 +1556,11 @@ def parse_docstring(self, docstring, namespace, start):
         PythonStringSource = dynamic_class("sage.doctest.sources.PythonStringSource",
                                            (StringDocTestSource, PythonSource))
         min_indent = self.parser._min_indent(docstring)
-        pysource = '\n'.join([l[min_indent:] for l in docstring.split('\n')])
+        pysource = '\n'.join(l[min_indent:] for l in docstring.split('\n'))
         inner_source = PythonStringSource(self.basename, pysource,
                                           self.options,
-                                          self.printpath, lineno_shift=start+1)
+                                          self.printpath,
+                                          lineno_shift=start + 1)
         inner_doctests, _ = inner_source._create_doctests(namespace, True)
         safe_docstring = inner_source._neutralize_doctests(min_indent)
         outer_doctest = self.parser.get_doctest(safe_docstring, namespace,

src/sage/graphs/graph_database.py

@@ -666,7 +666,7 @@ def show(self, max_field_size=20, with_picture=False):
         """
         relabel = {}
         for col in valid_kwds:
-            relabel[col] = ' '.join([word.capitalize() for word in col.split('_')])
+            relabel[col] = ' '.join(word.capitalize() for word in col.split('_'))
 
         if re.search('SELECT .*degree_sequence.* FROM', self.__query_string__):
             format_cols = {'degree_sequence': data_to_degseq}

src/sage/groups/matrix_gps/matrix_group.py

@@ -348,7 +348,7 @@ def _latex_(self):
             0 & 1
             \end{array}\right) \right\rangle
         """
-        gens = ', '.join([latex(x) for x in self.gens()])
+        gens = ', '.join(latex(x) for x in self.gens())
         return '\\left\\langle %s \\right\\rangle' % gens
 
     def sign_representation(self, base_ring=None, side="twosided"):

src/sage/groups/perm_gps/permgroup_element.pyx

@@ -1804,9 +1804,10 @@ cdef class PermutationGroupElement(MultiplicativeGroupElement):
             '(1,3)(2)'
         """
         cycles = self.cycle_tuples(singletons)
-        if len(cycles) == 0:
+        if not cycles:
             return '()'
-        return ''.join([repr(c) for c in cycles]).replace(', ',',').replace(',)',')')
+        text = ''.join(repr(c) for c in cycles)
+        return text.replace(', ', ',').replace(',)', ')')
 
     def cycle_type(self, singletons=True, as_list=False):
         r"""

src/sage/schemes/curves/closed_point.py

@@ -181,7 +181,7 @@ def _repr_(self):
             sage: pts[0]
             Point (x, y)
         """
-        return "Point ({})".format(', '.join([repr(g) for g in self.prime_ideal().gens()]))
+        return "Point ({})".format(', '.join(repr(g) for g in self.prime_ideal().gens()))
 
     def curve(self):
         """

src/sage/schemes/curves/curve.py

@@ -67,9 +67,9 @@ def _repr_(self):
         """
         if self.defining_ideal().is_zero() and self.ambient_space().dimension() == 1:
             return "{} Line over {}".format(self._repr_type(), self.base_ring())
-        else:
-            return "{} Curve over {} defined by {}".format(self._repr_type(), self.base_ring(),
-                 ', '.join([str(x) for x in self.defining_polynomials()]))
+        return "{} Curve over {} defined by {}".format(self._repr_type(),
+                                                       self.base_ring(),
+            ', '.join(str(x) for x in self.defining_polynomials()))
 
     def _repr_type(self):
         r"""

src/sage/schemes/curves/projective_curve.py

@@ -2038,7 +2038,7 @@ def riemann_roch_basis(self, D):
                 Dcoeffs.append(D.coefficient(coords[x[1]]))
             else:
                 Dcoeffs.append(0)
-        G = singular(','.join([str(x) for x in Dcoeffs]), type='intvec')
+        G = singular(','.join(str(x) for x in Dcoeffs), type='intvec')
         # call singular's brill noether routine and return
         T = X2[1][2]
         T.set_ring()

src/sage/schemes/projective/projective_space.py

@@ -853,7 +853,7 @@ def _repr_generic_point(self, v=None):
         """
         if v is None:
             v = self.gens()
-        return '(%s)' % (" : ".join([repr(f) for f in v]))
+        return '(%s)' % (" : ".join(repr(f) for f in v))
 
     def _latex_generic_point(self, v=None):
         """

src/sage/stats/time_series.pyx

@@ -310,10 +310,10 @@ cdef class TimeSeries:
         if len(self) > max_print:
             v0 = self[:max_print//2]
             v1 = self[-max_print//2:]
-            return '[' + ', '.join([format%x for x in v0]) + ' ... ' + \
-                         ', '.join([format%x for x in v1]) + ']'
+            return '[' + ', '.join(format%x for x in v0) + ' ... ' + \
+                         ', '.join(format%x for x in v1) + ']'
         else:
-            return '[' + ', '.join([format%x for x in self]) + ']'
+            return '[' + ', '.join(format%x for x in self) + ']'
 
     def __len__(self):
         """

src/sage/symbolic/pynac_impl.pxi

@@ -598,7 +598,7 @@ def py_latex_function_pystring(id, args, fname_paren=False):
         olist = [name]
     # print the arguments
     from sage.misc.latex import latex
-    olist.extend([r'\left(', ', '.join([latex(x) for x in args]),
+    olist.extend([r'\left(', ', '.join(latex(x) for x in args),
                   r'\right)'])
     return ''.join(olist)
 
@@ -646,10 +646,11 @@ cdef stdstring* py_print_fderivative(unsigned id, params,
     - args -- arguments of the function.
     """
     if all(tolerant_is_symbol(a) for a in args) and len(set(args)) == len(args):
-        diffvarstr = ', '.join([repr(args[i]) for i in params])
-        py_res = ''.join(['diff(',py_print_function_pystring(id,args,False),', ',diffvarstr,')'])
+        diffvarstr = ', '.join(repr(args[i]) for i in params)
+        py_res = ''.join(['diff(', py_print_function_pystring(id, args, False),
+                          ', ', diffvarstr, ')'])
     else:
-        ostr = ''.join(['D[', ', '.join([repr(int(x)) for x in params]), ']'])
+        ostr = ''.join(['D[', ', '.join(repr(int(x)) for x in params), ']'])
         fstr = py_print_function_pystring(id, args, True)
         py_res = ostr + fstr
     return string_from_pystr(py_res)

src/sage/topology/simplicial_set.py

@@ -868,7 +868,7 @@ def _repr_(self):
             s_1 s_0 v
         """
         if self.degeneracies():
-            degens = ' '.join(['s_{}'.format(i) for i in self.degeneracies()])
+            degens = ' '.join(f's_{i}' for i in self.degeneracies())
             return degens + ' {}'.format(self.nondegenerate())
         return 'Delta^{}'.format(self._dim)
 
@@ -903,7 +903,7 @@ def _latex_(self):
         else:
             simplex = "\\Delta^{{{}}}".format(self._dim)
         if self.degeneracies():
-            degens = ' '.join(['s_{{{}}}'.format(i) for i in self.degeneracies()])
+            degens = ' '.join(f's_{{{i}}}' for i in self.degeneracies())
             return degens + ' ' + simplex
         return simplex
 

src/sage/topology/simplicial_set_constructions.py

@@ -523,10 +523,10 @@ def __init__(self, maps=None):
                         continue
 
                     simplex_factors = tuple(zip(simplices, tuple(degens)))
-                    s = '(' + ', '.join(['{}'.format(_[0].apply_degeneracies(*_[1]))
-                                         for _ in simplex_factors]) + ')'
-                    ls = '(' + ', '.join(['{}'.format(latex(_[0].apply_degeneracies(*_[1])))
-                                          for _ in simplex_factors]) + ')'
+                    s = '(' + ', '.join('{}'.format(_[0].apply_degeneracies(*_[1]))
+                                        for _ in simplex_factors) + ')'
+                    ls = '(' + ', '.join('{}'.format(latex(_[0].apply_degeneracies(*_[1])))
+                                         for _ in simplex_factors) + ')'
                     simplex = AbstractSimplex(d, name=s, latex_name=ls)
                     translate[simplex_factors] = simplex
                     # Now compute the faces of simplex.
@@ -968,7 +968,7 @@ def _repr_(self):
             sage: S2.product(K, B)
             S^2 x Klein bottle x Classifying space of Multiplicative Abelian group isomorphic to C2
         """
-        return ' x '.join([str(X) for X in self._factors])
+        return ' x '.join(str(X) for X in self._factors)
 
     def _latex_(self):
         r"""
@@ -983,7 +983,7 @@ def _latex_(self):
             sage: latex(S2.product(RPoo, S2))
             S^{2} \times RP^{\infty} \times S^{2}
         """
-        return ' \\times '.join([latex(X) for X in self._factors])
+        return ' \\times '.join(latex(X) for X in self._factors)
 
 
 class ProductOfSimplicialSets_finite(ProductOfSimplicialSets, PullbackOfSimplicialSets_finite):
@@ -1934,7 +1934,7 @@ def _repr_(self):
             Smash product: (S^1 ^ RP^4 ^ S^1)
         """
         s = 'Smash product: ('
-        s += ' ^ '.join([str(X) for X in self._factors])
+        s += ' ^ '.join(str(X) for X in self._factors)
         s += ')'
         return s
 
@@ -1949,7 +1949,7 @@ def _latex_(self):
             sage: latex(S1.smash_product(RP4, S1))
             S^{1} \wedge RP^{4} \wedge S^{1}
         """
-        return ' \\wedge '.join([latex(X) for X in self._factors])
+        return ' \\wedge '.join(latex(X) for X in self._factors)
 
 
 class WedgeOfSimplicialSets(PushoutOfSimplicialSets, Factors):
@@ -2039,7 +2039,7 @@ def _repr_(self):
             Wedge: (Klein bottle v Klein bottle v Klein bottle)
         """
         s = 'Wedge: ('
-        s += ' v '.join([str(X) for X in self._factors])
+        s += ' v '.join(str(X) for X in self._factors)
         s += ')'
         return s
 
@@ -2054,7 +2054,7 @@ def _latex_(self):
             sage: latex(S1.wedge(RP4, S1))
             S^{1} \vee RP^{4} \vee S^{1}
         """
-        return ' \\vee '.join([latex(X) for X in self._factors])
+        return ' \\vee '.join(latex(X) for X in self._factors)
 
 
 class WedgeOfSimplicialSets_finite(WedgeOfSimplicialSets, PushoutOfSimplicialSets_finite):
@@ -2245,7 +2245,7 @@ def _repr_(self):
             Disjoint union: (Torus u Torus u RP^3)
         """
         s = 'Disjoint union: ('
-        s += ' u '.join([str(X) for X in self._factors])
+        s += ' u '.join(str(X) for X in self._factors)
         s += ')'
         return s
 
@@ -2260,7 +2260,7 @@ def _latex_(self):
             sage: latex(S1.disjoint_union(RP4, S1))
             S^{1} \amalg RP^{4} \amalg S^{1}
         """
-        return ' \\amalg '.join([latex(X) for X in self._factors])
+        return ' \\amalg '.join(latex(X) for X in self._factors)
 
 
 class DisjointUnionOfSimplicialSets_finite(DisjointUnionOfSimplicialSets,