py3: fix some remaining invalid escape sequences

Author: Frédéric Chapoton

src/sage/all.py

@@ -306,7 +306,7 @@ def _write_started_file():
     module='.*(IPython|ipykernel|jupyter_client|jupyter_core|nbformat|notebook|ipywidgets|storemagic)')
 # However, be sure to keep OUR deprecation warnings
 warnings.filterwarnings('default',
-    '[\s\S]*See http://trac.sagemath.org/[0-9]* for details.')
+    r'[\s\S]*See https\?://trac.sagemath.org/[0-9]* for details.')
 
 
 # Set a new random number seed as the very last thing

src/sage/combinat/root_system/type_Q.py

@@ -76,8 +76,8 @@ def __reduce__(self):
         return (CartanType, (self.letter, self.n+1))
 
     def index_set(self):
-        """
-        Returns index set for Cartan type Q.
+        r"""
+        Return the index set for Cartan type Q.
 
         The index set for type Q is of the form
         `\{-n, \ldots, -1, 1, \ldots, n\}`.
@@ -87,7 +87,7 @@ def index_set(self):
             sage: CartanType(['Q', 3]).index_set()
             (1, 2, -2, -1)
         """
-        return tuple(range(1,self.n+1)+range(-self.n,0))
+        return tuple(range(1, self.n + 1) + range(-self.n, 0))
 
     def _latex_(self):
         r"""
@@ -98,7 +98,7 @@ def _latex_(self):
             sage: latex(CartanType(['Q',4]))
             Q_{4}
         """
-        return "Q_{%s}"%(self.n+1)
+        return "Q_{%s}" % (self.n + 1)
 
     def root_system(self):
         """

src/sage/env.py

@@ -1,4 +1,4 @@
-"""
+r"""
 Sage Runtime Environment
 
 AUTHORS:
@@ -227,6 +227,7 @@ def _add_variable_or_fallback(key, fallback, force=False):
 # delete temporary variables used for setting up sage.env
 del opj, os, socket, version, site
 
+
 def sage_include_directories(use_sources=False):
     """
     Return the list of include directories for compiling Sage extension modules.

src/sage/misc/latex.py

@@ -330,7 +330,7 @@ def str_function(x):
         return x
     # Deal with special characters
     char_wrapper = r"{\char`\%s}"
-    x = "".join(char_wrapper % c if c in "#$%&\^_{}~" else c for c in x)
+    x = "".join(char_wrapper % c if c in r"#$%&\^_{}~" else c for c in x)
     # Avoid grouping spaces into one
     x = x.replace(" ", "{ }")
     # And dashes too, since it causes issues for the command line...
@@ -865,8 +865,9 @@ def _run_latex_(filename, debug=False, density=150, engine=None, png=False, do_i
         return "Error latexing slide."
     return return_suffix
 
+
 class LatexCall:
-    """
+    r"""
     Typeset Sage objects via a ``__call__`` method to this class,
     typically by calling those objects' ``_latex_`` methods.  The
     class :class:`Latex` inherits from this. This class is used in
@@ -1964,7 +1965,7 @@ def eval(self, x, globals=None, locals=None, mode='display',
             # part should end in "}}", so omit the last two characters
             # from y
             y = part[:closing-1]
-            for delimiter in """|"'`#%&,.:;?!@_~^+-/\=<>()[]{}0123456789E""":
+            for delimiter in r"""|"'`#%&,.:;?!@_~^+-/\=<>()[]{}0123456789E""":
                 if delimiter not in y:
                     break
             if delimiter == "E":
@@ -2420,7 +2421,7 @@ def repr_lincomb(symbols, coeffs):
                 # multiplication sign in
                 try:
                     if bv in CC:
-                        s += "%s\cdot %s" % (coeff, b)
+                        s += r"%s\cdot %s" % (coeff, b)
                     else:
                         s += "%s%s" % (coeff, b)
                 except Exception:
@@ -2615,7 +2616,7 @@ def latex_variable_name(x, is_fname=False):
         # * The "\d|[.,]" means "decimal digit" or period or comma
         # * The "+" means "1 or more"
         # * The "$" means "at the end of the line"
-        m = re.search('(\d|[.,])+$',x)
+        m = re.search(r'(\d|[.,])+$', x)
         if m is None:
             prefix = x
             suffix = None
@@ -2630,15 +2631,16 @@ def latex_variable_name(x, is_fname=False):
             for sym in symtable.values():
                 if sym[0] == '_' and sym[1:] == suffix:
                     return latex_variable_name(suffix)
-    if suffix and len(suffix) > 0:
+    if suffix and len(suffix):
         # handle the suffix specially because it very well might be numeric
         # I use strip to avoid using regex's -- It makes it a bit faster (and the code is more comprehensible to non-regex'ed people)
-        if suffix.strip("1234567890")!="":
+        if suffix.strip("1234567890") != "":
             suffix = latex_variable_name(suffix, is_fname) # recurse to deal with recursive subscripts
-        return '%s_{%s}'%(latex_varify(prefix, is_fname), suffix)
+        return '%s_{%s}' % (latex_varify(prefix, is_fname), suffix)
     else:
         return latex_varify(prefix, is_fname)
 
+
 class LatexExamples():
     r"""
     A catalogue of Sage objects with complicated ``_latex_`` methods.

src/sage/modular/modform/ambient.py

@@ -558,9 +558,11 @@ def _q_expansion(self, element, prec):
     ####################################################################
     @cached_method
     def _dim_cuspidal(self):
-        """
+        r"""
         Return the dimension of the cuspidal subspace of this ambient
-        modular forms space. For weights `k \ge 2` this is computed using a
+        modular forms space.
+
+        For weights `k \ge 2` this is computed using a
         dimension formula. For weight 1, it will trigger a computation of a
         basis of `q`-expansions using Schaeffer's algorithm, unless this space
         is a space of Eisenstein forms only, in which case we just return 0.
@@ -583,7 +585,8 @@ def _dim_cuspidal(self):
         if self._eis_only:
             return 0
         if arithgroup.is_Gamma1(self.group()) and self.character() is not None:
-            return self.group().dimension_cusp_forms(self.weight(), self.character())
+            return self.group().dimension_cusp_forms(self.weight(),
+                                                     self.character())
         else:
             return self.group().dimension_cusp_forms(self.weight())
 

src/sage/schemes/elliptic_curves/isogeny_small_degree.py

@@ -708,7 +708,7 @@ def isogenies_2(E, minimal_models=True):
 
 
 def isogenies_3(E, minimal_models=True):
-    """
+    r"""
     Return a list of all 3-isogenies with domain ``E``.
 
     INPUT:
@@ -748,7 +748,7 @@ def isogenies_3(E, minimal_models=True):
     f3 = E.division_polynomial(3)
     x3 = sorted(f3.roots(multiplicities=False))
     x = f3.parent().gen()
-    ff = [x-x3i for x3i in x3]
+    ff = [x - x3i for x3i in x3]
     from sage.rings.number_field.number_field_base import is_NumberField
     model = "minimal" if minimal_models and is_NumberField(E.base_field()) else None
     isogs = [E.isogeny(f, model=model) for f in ff]
@@ -757,7 +757,8 @@ def isogenies_3(E, minimal_models=True):
 # 6 special cases: `l` = 5, 7, 13 and `j` = 0, 1728.
 
 def isogenies_5_0(E, minimal_models=True):
-    r"""Returns a list of all the 5-isogenies  with domain ``E`` when the
+    r"""
+    Return a list of all the 5-isogenies  with domain ``E`` when the
     j-invariant is 0.
 
     INPUT: