sagemathgh-38165: simplify some calls to join

    
by avoiding to create the inner list

### 📝 Checklist

- [x] The title is concise and informative.
- [x] The description explains in detail what this PR is about.
    
URL: sagemath#38165
Reported by: Frédéric Chapoton
Reviewer(s): Matthias Köppe

src/sage/combinat/nu_tamari_lattice.py

@@ -173,13 +173,13 @@ def delta_swap(p, k, delta):
         raise ValueError("the index is greater than the length of the path")
     # if delta is None:
     #     delta = [len(_) for _ in str(p._nu).split(sep='1')[1:]]
-    if k == 0 or p[k-1] == 1:
+    if k == 0 or p[k - 1] == 1:
         raise ValueError("there is no such covering move")
     found = False
     i = p[:k].count(1)
     j = k
     alt = 0
-    while not found and j <= p.length()-1:
+    while not found and j <= p.length() - 1:
         if p[j]:
             alt += delta[i]
             i += 1
@@ -188,9 +188,10 @@ def delta_swap(p, k, delta):
         if alt == 0:
             found = True
         j += 1
-    q = p[:k-1] + p[k:j] + [p[k-1]] + p[j:]
+    q = p[:k - 1] + p[k:j] + [p[k - 1]] + p[j:]
     return NuDyckWord(q, p._nu)
 
+
 def AltNuTamariLattice(nu, delta=None):
     r"""
     Return the `(\delta,\nu)`-Tamari lattice (or alt `\nu`-Tamari lattice).
@@ -253,12 +254,12 @@ def AltNuTamariLattice(nu, delta=None):
 
     - [CC2023]_
     """
-    if not( (isinstance(nu, (list, tuple)) and all(x in [0, 1] for x in nu)) or
-            (isinstance(nu, str) and all(x in ['0', '1'] for x in nu)) ):
+    if not ((isinstance(nu, (list, tuple)) and all(x in [0, 1] for x in nu)) or
+            (isinstance(nu, str) and all(x in ['0', '1'] for x in nu))):
         raise ValueError("nu must be a list or a string of 0s and 1s")
     nu = [int(a) for a in nu]
     # transforms nu in a sequence of 0s and 1s if it is a list
-    nu = ''.join([str(a) for a in nu])
+    nu = ''.join(str(a) for a in nu)
     # produces delta if delta is None, and check that delta is valid otherwise
     deltamax = [len(a) for a in nu.split(sep='1')[1:]]
     if delta is None:
@@ -270,4 +271,4 @@ def covers(p):
         return [delta_swap(p, k, delta=delta) for k in range(1, p.length())
                 if not p[k - 1] and p[k]]
     return LatticePoset({p: covers(p) for p in NuDyckWords(nu)},
-                        check=False)
+                        check=False)

src/sage/geometry/integral_points.pxi

@@ -948,7 +948,7 @@ cdef class Inequality_int:
             'integer: (2, 3, 7) x + -5 >= 0'
         """
         s = 'integer: ('
-        s += ', '.join([str(self.A[i]) for i in range(self.dim)])
+        s += ', '.join(str(self.A[i]) for i in range(self.dim))
         s += ') x + ' + str(self.b) + ' >= 0'
         return s
 

src/sage/geometry/toric_lattice.py

@@ -1163,7 +1163,7 @@ def _repr_(self):
         """
         s = 'Sublattice '
         s += '<'
-        s += ', '.join(map(str,self.basis()))
+        s += ', '.join(map(str, self.basis()))
         s += '>'
         return s
 
@@ -1186,7 +1186,7 @@ def _latex_(self):
              \\left(0,\\,4,\\,8\\right)_{L}\\right\\rangle'
         """
         s = '\\left\\langle'
-        s += ', '.join([ b._latex_() for b in self.basis() ])
+        s += ', '.join(b._latex_() for b in self.basis())
         s += '\\right\\rangle'
         return s
 

src/sage/graphs/graph_input.py

@@ -103,8 +103,8 @@ def from_sparse6(G, g6_string):
         k = int((ZZ(n) - 1).nbits())
         ords = [ord(i) for i in s]
         if any(o > 126 or o < 63 for o in ords):
-            raise RuntimeError("the string seems corrupt: valid characters are \n" + ''.join([chr(i) for i in range(63, 127)]))
-        bits = ''.join([int_to_binary_string(o-63).zfill(6) for o in ords])
+            raise RuntimeError("the string seems corrupt: valid characters are \n" + ''.join(chr(i) for i in range(63, 127)))
+        bits = ''.join(int_to_binary_string(o-63).zfill(6) for o in ords)
         if not k:
             b = [int(x) for x in bits]
             x = [0] * len(b)

src/sage/groups/finitely_presented.py

@@ -799,7 +799,7 @@ def __init__(self, free_group, relations, category=None):
         ParentLibGAP.__init__(self, parent_gap)
         Group.__init__(self, category=category)
 
-    def _repr_(self):
+    def _repr_(self) -> str:
         """
         Return a string representation.
 
@@ -813,7 +813,7 @@ def _repr_(self):
             'Finitely presented group < a, b | a, b^3 >'
         """
         gens = ', '.join(self.variable_names())
-        rels = ', '.join([str(r) for r in self.relations()])
+        rels = ', '.join(str(r) for r in self.relations())
         return 'Finitely presented group ' + '< ' + gens + ' | ' + rels + ' >'
 
     def _latex_(self):

src/sage/lfunctions/dokchitser.py

@@ -467,12 +467,12 @@ def repl(m):
             raise TypeError("v (=%s) must be a list, tuple, or string" % v)
         else:
             CC = self.__CC
-            v = ','.join([CC(a)._pari_init_() for a in v])
+            v = ','.join(CC(a)._pari_init_() for a in v)
             self._gp_eval('Avec = [%s]' % v)
             if w is None:
                 self._gp_call_inst('initLdata', '"Avec[k]"', cutoff)
             else:
-                w = ','.join([CC(a)._pari_init_() for a in w])
+                w = ','.join(CC(a)._pari_init_() for a in w)
                 self._gp_eval('Bvec = [%s]' % w)
                 self._gp_call_inst('initLdata', '"Avec[k]"', cutoff,
                                    '"Bvec[k]"')

src/sage/libs/eclib/mwrank.pyx

@@ -154,7 +154,7 @@ def initprimes(filename, verb=False):
 
         sage: import tempfile
         sage: with tempfile.NamedTemporaryFile(mode='w+t') as f:
-        ....:     data = ' '.join([str(p) for p in prime_range(10^7,10^7+20)])
+        ....:     data = ' '.join(str(p) for p in prime_range(10^7, 10^7 + 20))
         ....:     _ = f.write(data)
         ....:     f.flush()
         ....:     mwrank_initprimes(f.name, verb=True)

src/sage/matrix/matrix1.pyx

@@ -291,9 +291,9 @@ cdef class Matrix(Matrix0):
             sage: a._mathematica_init_()                                                # needs sage.symbolic
             '{{Pi, Sin[x]}, {Cos[x], Exp[-1]}}'
         """
-        return '{' + ', '.join([v._mathematica_init_() for v in self.rows()]) + '}'
+        return '{' + ', '.join(v._mathematica_init_() for v in self.rows()) + '}'
 
-    def _magma_init_(self, magma):
+    def _magma_init_(self, magma) -> str:
         r"""
         Return a string that evaluates in the given Magma session to this
         matrix.

src/sage/misc/cython.py

@@ -500,7 +500,7 @@ def cython_lambda(vars, expr, verbose=0, **kwds):
     if isinstance(vars, str):
         v = vars
     else:
-        v = ', '.join(['%s %s' % (typ, var) for typ, var in vars])
+        v = ', '.join('%s %s' % (typ, var) for typ, var in vars)
 
     s = """
 cdef class _s:

src/sage/misc/sage_input.py

@@ -2185,7 +2185,7 @@ def __repr__(self):
         """
         kind = "list" if self._sie_is_list else "tuple"
         return "{%s: (%s)}" % \
-            (kind, ', '.join([repr(v) for v in self._sie_values]))
+            (kind, ', '.join(repr(v) for v in self._sie_values))
 
     def _sie_referenced(self):
         r"""
@@ -2290,8 +2290,8 @@ def __repr__(self):
             {dict: {{atomic:'keaton'}:{atomic:'general'}, {atomic:'chan'}:{atomic:'master'}}}
         """
         return "{dict: {%s}}" % \
-            ', '.join([repr(key) + ':' + repr(val)
-                       for key, val in self._sie_entries])
+            ', '.join(repr(key) + ':' + repr(val)
+                      for key, val in self._sie_entries)
 
     def _sie_referenced(self):
         r"""
@@ -2454,7 +2454,7 @@ def _sie_format(self, sif):
         op = self._sie_op
         fop = op
         if op == '**':
-            lhs = sif.format(self._sie_operands[0], _prec_exponent+1)
+            lhs = sif.format(self._sie_operands[0], _prec_exponent + 1)
             rhs = sif.format(self._sie_operands[1], _prec_exponent)
             if self._sie_builder.preparse():
                 return '%s^%s' % (lhs, rhs), _prec_exponent
@@ -2475,7 +2475,7 @@ def _sie_format(self, sif):
             raise ValueError('Unhandled op {} in SIE_binary'.format(op))
 
         lhs = sif.format(self._sie_operands[0], prec)
-        rhs = sif.format(self._sie_operands[1], prec+1)
+        rhs = sif.format(self._sie_operands[1], prec + 1)
         return '%s%s%s' % (lhs, fop, rhs), prec
 
 
@@ -2857,7 +2857,7 @@ def _sie_add_command(self, sif):
                     if len(self._sie_gens) == 1:
                         sif._commands += '%s = %s.gen()\n' % (self._sie_gens[0]._sie_get_varname(sif), self._sie_get_varname(sif))
                     else:
-                        sif._commands += '%s = %s.gens()\n' % (','.join([g._sie_get_varname(sif) for g in self._sie_gens]), self._sie_get_varname(sif))
+                        sif._commands += '%s = %s.gens()\n' % (','.join(g._sie_get_varname(sif) for g in self._sie_gens), self._sie_get_varname(sif))
             self._sie_generated = True
 
     def _sie_format(self, sif):

src/sage/modules/fp_graded/steenrod/module.py

@@ -245,7 +245,7 @@ def export_module_definition(self, powers_of_two_only=True):
 
         # Print the degrees of the additive generators.
         ret = '%d %s' % (len(additive_generator_degrees),
-                         ' '.join(['%d' % x for x in additive_generator_degrees]))
+                         ' '.join('%d' % x for x in additive_generator_degrees))
 
         # A private function which transforms a vector in a given dimension
         # to a vector of global indices for the basis elements corresponding

src/sage/rings/number_field/totallyreal_rel.py

@@ -287,7 +287,7 @@ def __init__(self, F, m, B, a=None):
         Z_Fbasis = self.Z_F.basis()
 
         # Initialize variables.
-        if a == []:
+        if not a:
             # No starting input, all polynomials will be found; initialize to zero.
             self.a = [0]*m + [1]
             self.amaxvals = [[]]*m
@@ -301,7 +301,7 @@ def __init__(self, F, m, B, a=None):
             import numpy
             for i in range(len(anm1s)):
                 Q = [[v(m*x) for v in self.Foo] + [0] for x in Z_Fbasis] + [[v(anm1s[i]) for v in self.Foo] + [10**6]]
-                pari_string = '['+';'.join([','.join(["%s" % ii for ii in row]) for row in zip(*Q)])+']'
+                pari_string = '[' + ';'.join(','.join("%s" % ii for ii in row) for row in zip(*Q)) + ']'
                 adj = pari(pari_string).qflll()[self.d]
                 anm1s[i] += sum([m*Z_Fbasis[ii]*int(adj[ii])//int(adj[self.d]) for ii in range(self.d)])
 

src/sage/rings/valuation/value_group.py

@@ -591,7 +591,7 @@ def _repr_(self):
         """
         if self.is_trivial():
             return "Trivial Additive Abelian Semigroup"
-        return "Additive Abelian Semigroup generated by %s" % (', '.join([repr(g) for g in self._generators]),)
+        return "Additive Abelian Semigroup generated by %s" % (', '.join(repr(g) for g in self._generators),)
 
     def __add__(self, other):
         r"""